Time Series Analysis Exam Questions

On the time series speed analysis of the statement, the correct ().

[Answer]: A, B, D

AC two, fixed base development speed and ring development speed of the two there is a certain quantitative dependence: ① fixed base development speed is equal to the corresponding period of the ring development speed of the product of the chain; ② the ratio of the fixed base development speed of the two adjacent periods is equal to the corresponding period of the ring development speed. b, the average growth rate reflects the phenomenon of a certain period of time, the average growth rate = average development speed – 1; D, when applying speed analysis of practical problems, when the application of speed analysis, the average growth rate = average development speed – 1. B, the average growth rate reflects the general degree of phenomena in a certain period of time, period by period growth (decrease) changes, the average growth rate = average development rate -1; D, in the application of speed analysis of practical problems, when the value of the indicators in the time series of 0 or negative, it is not appropriate to calculate the speed; E, the calculation of the average rate of development is usually used in the method of geometric averages.

When analyzing and calculating time series, growth can be divided into period-by-period growth and cumulative growth, the difference between the two is ()

[Answer]: C

This question is about growth and average growth. According to the different methods of determining the base period, growth is divided into period-by-period growth and cumulative growth.

Economist examination economic basic statistics (four)

Fourth, time series

(a) time series and its classification

Time series are divided into: absolute number time series, relative number time series and average time series.

Absolute number of time series can be divided into period series and point series.

(B) the level of time series analysis

1. The level of development: the time series corresponds to the value of the specific time indicators.

2. Average level of development: sequential average or dynamic average, is the average of the development level of each period in the time series calculated.

Calculation method:

(1) the calculation of the ordinal average of the absolute number of time series:

a. Periodic series, the data of each period can be summed up and divided by the number of periods.

b. Points in time series, if the day-by-day registration of continuous points in time, the simple arithmetic average method; if not day-by-day registration, the weighted arithmetic average method. For intermittent points in time, if the interval is equal, then first seek the average of each time interval, and then simple arithmetic average of these averages; if the interval is not equal, then use the weighted arithmetic average.

(2) Relative or average time series of sequential averages of the calculation: first of all, respectively, the numerator indicators and denominator indicators of the time series of sequential averages, and then compared.

3. Growth and average growth

(1) Growth: the difference between the level of the reporting period and the base period level in the time series, used to describe the absolute amount of phenomena in the observation period growth. According to the use of different base period, divided into period-by-period growth, cumulative growth.

The period-by-period growth is the difference between the level of the reporting period and the level of the previous period, indicating the absolute amount of growth in the current period compared with the previous period;

The cumulative growth is the difference between the level of the reporting period and the level of a fixed period, describing the absolute amount of growth in the reporting period compared with a fixed period.

The sum of the period-by-period growth over the entire observation period equals the cumulative growth at the very end.

(2) Mean growth: the ordinal average of the period-by-period growth in the time series.

(C) the speed of time series analysis

1. Development and growth rate

(1) development rate: the ratio of the level of development in the reporting period to the level of development in the base period, used to describe the degree of development of the phenomenon in the period of observation changes

Fixed-base development rate is equal to the corresponding period of time in the development of the speed of the chain multiplied.

The ratio of the rate of development of the fixed base in two adjacent periods is equal to the rate of development of the ring in the corresponding period.

(2) growth rate: also known as the growth rate, is the ratio of growth to the base period level, used to describe the relative growth of the phenomenon.

According to the different base period, the growth rate can be divided into a fixed base growth rate and ring growth rate, there is no direct conversion relationship between the two, in the ring growth rate deduced from the fixed base growth rate, you can first multiply the ring growth rate plus 1, and then reduce the results by 1, that is, to get the fixed base growth rate.

2. Average development speed and average growth rate

Average development speed: the average of the ring development speed of each period, used to describe the phenomenon in the whole observation period the average development of the degree of change

The average growth rate (average growth rate): used to describe the phenomenon in the whole observation period the average degree of change in the growth of the phenomenon, which is usually used in the average development speed minus one to It is usually obtained by subtracting 1 from the average rate of development.

3. Analysis and application of speed

Growth 1% absolute value: indicates the absolute amount of increase per percentage point of growth. Equal to the period-by-period growth volume / ring growth rate.

Analysis of Midterm Language Papers in Primary Schools

Analysis may refer to: financial analysis; systems analysis; analytical chemistry; analytical mechanics; structural analysis (civil engineering); modal flow analysis (plastics); frequency analysis (cryptography); time series analysis (statistics); mathematical analysis (mathematics); real analysis; complex analysis; moderated analysis; generalized analysis dimensional analysis; semantic analysis (linguistics); phonological analysis; philosophical analysis. Analysis (Linguistics); Philosophical Analysis. Here is my collection of elementary school midterm language paper analysis templates (selected 5).

Primary school midterm language paper analysis article 1

The language final test, based on the new language standard, the test questions cover a wide range of difficulty and moderately easy, student development-oriented, focusing on the development of students’ abilities in all aspects. The test paper is an all-round test of students’ language literacy in terms of hanyu pinyin, literacy, writing, language accumulation and reading comprehension. The following is a brief overview of the students’ answers and the improvement of future teaching.

One, the student test

The number of references 63 people, 100 points 21 people, 80-89 points 3 people, the lowest score of 83 points, pass rate of 100%, the rate of excellence 95%, the average score of 96.8 points.

The specific analysis of the paper

The first question: “Look at the pinyin and write the words” mainly examines the students’ spelling and writing ability. Although most of the students have mastered pinyin and completed it well, individual students were not serious about spelling, and there were misspellings. For example, they wrote “windmill” as “flyer”, “self” as “self”, “east” as “east”, “east” as “east”, “east” as “east”, “east” as “east”, and “east” as “east”. “east” as “car”.

The second question: linking, which requires students to connect the Chinese characters with the corresponding syllables, mainly examines students’ literacy and spelling skills. Some students got the words “艳” and “藏” wrong because they don’t appear very often.

The third question: Write the words with the names of the strokes and form the words according to the requirements, which mainly examines the students’ ability to master the names of the strokes and their ability to form the words. Most of the students mastered the names of the strokes, but there were many mistakes in the formation of the word “and”, such as “big”, “round”, “red”, etc. The students were able to write down the names of the strokes and form words.

Question 4: Classify children by radicals. Students did well in this question, but some students missed the words.

The fifth question: find out the words that are not in the same category in each group. Most of the students did well, but some of them chose “fox” in the group of words “fox, squirrel, swan, elephant”.

The sixth question: find the antonyms in the sentences, this question students can find the antonyms, finished well, but individual students due to the writing is not serious, the word “more” writing is not standardized.

The seventh question: the following words into a coherent sentence, for the first-grade students just contact with the sentence is a little difficult, belong to improve the question. But usually quite a lot of practice, so most students finished well, a few students have missed punctuation. Examples of mistakes are: my beloved hometown creek.

The eighth question: reading comprehension, mainly to examine the students’ ability to understand the language. The first question is written in the text of several colors and drawn with a wavy line. Some students missed to fill in; the second sub-question in the text is who persuade who, the answer appears more misspelled words, for example: “sister” written as “group”, “brother” written as “The third sub-question is to write a sentence with “and”, most students can write a complete sentence with the word “and”, some students have misspelled words and wrong syllables in their sentences. Some students missed punctuation.

Third, for the existence of problems, the teaching measures taken

After analyzing the test papers and students’ answers, I think the following aspects of language teaching need to be paid attention to:

1, for the teaching of hanyu pinyin, it is necessary to grasp the instrumental nature of the teaching to cultivate the students’ ability to recognize and read the words with the help of hanyu pinyin.

2, for the teaching of writing, we must teach students the correct way to hold the pen and carry the pen, so that students can master the posture of writing, and can write according to the order of strokes, write the characters correctly and beautifully.

3. In ordinary teaching, to strengthen the training of students’ oral expression ability, guide students to say complete sentences.

4. In ordinary teaching, pay attention to language . Accumulation, expand students’ knowledge, and appropriately increase students’ reading to consolidate literacy and improve reading comprehension.

5, in the usual teaching should strengthen the training, in doing language exercises, should aim to cultivate students to carefully examine the question, answer the question according to the requirements as well as carefully check the habit of answering the question.

Primary school midterm language paper analysis of the 2

The language midterm paper questions are moderately difficult, not only pay attention to the examination of students’ mastery of basic knowledge, but also pay attention to the examination of students to analyze the problem, problem-solving ability, to promote the continuous improvement of the students’ language skills. Moreover, most of the test content is students have seen and practiced the topic, as long as the questions carefully will experience the joy of success.

I. Problems

II. Rectification Measures

1. Though I have finished learning pinyin, I will continue to infiltrate pinyin teaching in my future teaching and try to let students use hanyu pinyin flexibly.

2. Writing. Usually every homework should be strictly required, for not seriously writing homework should be determined to require students to rewrite. Usually, we should give students some ways to practice writing. Usually homework should be less and fine, to leave enough time to students, to avoid the phenomenon of students in order to seek fast and reduce the quality of the requirements of the phenomenon.

4. Educate students to pay attention to the accumulation of knowledge in their studies and improve their language skills.

5, let the children see more practice questions, targeted to cultivate children to carefully review the questions, independent answer, think before writing, after completing all the exercises but also carefully check the habit.

6, develop students’ drawing ability.

Primary school midterm language paper analysis chapter 3

Achievement analysis:

Class average score: 88.86

Excellent rate: 55.6%

Failure rate: 0%

Second, test analysis:

This set of tests a total of eleven questions, around the basic, accumulation and application, reading practice, assignments, show several modules The test; the difficulty of the questions is moderate, there is a certain level, suitable for third-grade students. Among them, the basic questions are mainly based on the textbook words, the original text, words focus on students’ similar words, polyphonic words, confusing words, words with the test; extracurricular reading content relative to the previous questions, the difficulty is reduced, the main test according to the original content of the content of the fill in the content and the understanding of the article; writing through the unit’s two assignments proposition to training, that is, write a clear process, to express their own feelings.

The overall difficulty of the paper is moderate, the number of questions is not large, the textbook knowledge accounted for about 80% of the volume, reflecting the concept of consolidation of the foundations and the cultivation of the ability to pay equal attention.

Three, student answer analysis:

In conjunction with the actual scores of the paper, reflecting the problem of roughly the following points: the foundation is not solid, polyphonic words “fresh, cages” grouping error, fully explains the basic words mastery is not in place. Text content learning is not solid, such as the ninth question, the test is silent recitation, many students fill in the wrong, in the review should increase the poetry, the accumulation of silent writing. Learned knowledge can not be flexibly applied, such as reading comprehension of the tenth question. Did not understand the meaning of the question, there is a problem of not reading through the text. Essay statements do not make sense, or the main idea is not clear, did not write details, can not use punctuation correctly.

Four, a few reflections

1, word study can not be relaxed for a moment, the word list words in each class for a unified dictation, easy to wrong words to focus on the explanation of the arrangement of one-on-one dictation, will help to improve the word off the pass rate of the students, but also to ensure that auxiliary work to the end of the poor.

2. Memorization is the most important thing. This book of selected ancient poems, garden cumulative need to recite more, most of the students recite on no problem, focusing on the inability to understand the content of the memorization or individual words written with pinyin or aliases. Therefore, in the process of memorization, adhere to the need to memorize the content of the understanding, timely mimeograph, difficult to write and easy to write the wrong words to focus on comments, copying for consolidation.

3, reading training needs to be strengthened and guidance. From the reading answer situation can be seen, some students answer the content or detached from the text, or find the wrong information. Therefore, in the text review, pay attention to the child’s ability to collect information, text review focus on the form of questions for review, encourage children to circle the answers from the textbook, take notes, and individual students to individual counseling.

4, essay still need guidance. Composition focuses on the smoothness of the statement, manner and theme, which will become the focus of the next semester guidance.

This midterm test basically reflects the status of students’ learning since they have been in school. The students’ foundation is generally solid, but the flexible application of knowledge needs to be improved, the development of reading habits and independent reading ability is still insufficient. In the future teaching, teachers still need to continue to increase the basic vocabulary dictation, cultivate good reading habits, improve learning efficiency, so that students have gained.

Primary school midterm language paper analysis chapter 4

From the overall view of this test question involves a wider range of knowledge, the examination of the form of multi-Yanghua, but a small number of students in this class answered more satisfactory, the results are relatively good. Most students answered less than ideal.

Write down the learned consonants in order

Most of the students wrote this question correctly. However, individuals wrote all the vowels and rhymes without separating them. Today I asked some of the students and they told me that they didn’t know the required words, they didn’t know what some of them were, so they wrote all the vowels and rhymes.

Corrective measures: set aside one language class a week to practice more examination items about pinyin. One is to let students recognize the requirements, and the other is to consolidate and review pinyin.

Find a Friend

Many students in the program don’t know what to make him do? Do not know the two sides of the pinyin and the middle word connected. Some students were also not familiar with pinyin and could not spell the correct syllables, so they connected the wrong ones.

Corrective measures: pay more attention to spelling training in weekday classes.

Memorize and write.

Except for the unlearned, the other and the content of the students 100% memorized, but fill in the error. Reason (1) most students can not write. (2)They don’t know how many words to fill in the blanks.

Corrective measures: in the future in the classroom more know the training.

Connect the lines according to the content of the learned children’s song. The reason for the loss of marks is that the student’s literacy is too small.

Corrective measures: in the future to guide students to increase the amount of literacy, reading class to encourage students to read more, more literacy. And evaluate the winners every time.

In short, in the future, we should try to expand the students’ literacy by all means, and make more papers so that students can recognize the test papers. On the other hand try to improve the efficiency of the classroom and bring up the students’ grades. The end-of-term test to achieve good results.

Primary school midterm language paper analysis article 5

I, see pinyin write words

This question is mainly to test the students’ writing ability, in the field character grid students how to write correctly, how to write correctly and evenly according to the radicals. Overall the score rate of this question is not high, about 85%. The main reason for the loss of points lies in the students’ inability to write correctly, the phenomenon of the wrong word, the most points are lost on the word “hongri”. Personally, I think that teachers in teaching should increase the students’ writing efforts, seriously teach students how to write correctly, write correctly.

II. Write words with the following radicals and form words

This question tests students’ knowledge of the radicals of words and their ability to form words. On the whole, students mastered this part of the basic knowledge well, scoring more than 95%, and lost the most points for the radical “页”, probably because this radical is used less in Chinese characters or is not good for word formation.

Three: Compare and Form Words

The score for this question was high, around 97%. Second-grade students are still very good at recognizing similar words, and probably because the two similar words listed in the question are often seen, the score rate of this question is high. The main missing points were in the two groups of words “己、已” and “晴、睛”. The difference between the two characters “晴、眼” is that “晴” is related to the sun, so its radical is “日”, and “眼” is related to “eyes”. “is related to “eye”, so its radical is “目” instead of “日”.

IV. Fill in the appropriate words

This question mainly tests how students can use appropriate words to represent common objects in daily life. Students are still clear about the use of some quantifiers, but the questioner did not check carefully when the question, so that the “six () knife” error, so that students have no way to fill in, and then the answer was not carefully checked, was “four flowers”, the answer was given “four flowers”. The answer was “four flowers”, but the answer was given as “four flowers”.

Fifth, fill in the antonym

The question of the students’ score rate is quite high, up to 98%. The main loss of points is the word “past”, I think, its antonym should be “future” or “future”, and the answer is given as “now”. The answer was given as “present”, which I personally did not think was appropriate. Students also did not know the antonym for ‘past’ and almost all marks were lost.

Sixth, complete the sentences and punctuate them

This question tests students’ ability to form a sentence, and students fill in sentences that have a certain logical relationship according to the words listed in the question to form a sentence. Students did well on the 1st sub-question and were able to complete it as well as fill in the correct punctuation. Students did not answer the 2nd and 3rd sub-questions well, especially the 3rd sub-question, in which students lost a high percentage of marks, either by failing to say a complete sentence or by failing to add the correct punctuation marks.

VII. Fill in the blanks according to the original text

This question has a high rate of students’ scores, above 99%, which shows that the students’ mastery of the text is still quite good, but only about 1% of the students made a mistake in the words and lost 1-2 points.

VIII. Read and Arrange

This question requires students to arrange the listed sentences into a paragraph according to a certain logical relationship, which is required to be carried out within (). The score for this question was not high, around 56%, mainly because students were not very clear about the logical relationship between the first and the second sentences, or perhaps because they could not read the requirements of the question, and therefore lost some marks.

Nine, guess the maze

The questioner listed a small curve, creating a small problem for students, so that students just see the customers in the barber store, not really open their minds to think. The maze of words listed was also relatively difficult. Students scored low on this question.

Ten, look at the picture writing

The title gives a labor scene, the picture has two people, one pulling a cart and one pushing a cart, the car is loaded with some perhaps fruit things, the two people are talking about what. As long as the students can write a few sentences according to the requirements listed in the title can score, but most of the students write a bad (about 80%) Some students can only write a sentence and incomplete, visible in the lack of writing skills of our students, as well as the observation ability is not strong, should be more training.

The model test for smooth time series analysis

By 丨meizi

Source 丨medical mathematical thinking cloud classroom (ID:Datamedi)

After determining the caliber of the fitted model, we also have to carry out the necessary tests on the fitted model. The tests referred to here are the significance test of the model and the significance test of the parameters.

01

The significance test of the model

The significance test of the model is mainly the validity of the model. Whether a model is significant and valid mainly depends on the adequacy of the extracted information.

A good fitting model should be able to extract almost all of the sample-related information in the sequence of observations, i.e., the sequence of residuals should be a white noise sequence. Such a model is called a significantly efficient model.

On the contrary, if the residual sequence is a non-white noise sequence, it means that there is still relevant information left in the sequence that has not been extracted, which indicates that the fitted model is not effective enough, and it is usually necessary to choose another model and re-fit it. Therefore, the significance test of the model is the white noise test of the residual series.

1.AR(p) model test

Test the significance of the fitted model of the sequence of the number of new mileage added to China’s postal routes and rural delivery routes each year from 1950 to 2008.

mileage<-read.table(“mileage.txt”,header=T)

miles<-ts(mileage[2],start=1950)

x.fit&. lt;-arima(miles,order=c(2,0,0),method=”ML”)

##White noise test for residual x.fit$resial

for(iin1:2)print(Box.test(x.fit$ resial,lag=6*i))

The result is as follows:

P>0.05,Accept the original hypothesis that the residuals are white noise, so the fitted model is significantly valid.

2.MA(q) model test

Testing the significance of the fitted model of OVERSHORT series for 57 consecutive days at a gas station in Colorado, USA.

ver<-read.table(“overshort.txt”,header=T)

overshort<-ts(over[2],start=1)

overshort. fit<-arima(overshort,order=c(0,0,1))

##White noise test for residuals overshort.fit.fit$resial

for(iin1:2)print(Box.test( overshort.fit$resial,lag=6*i))

The result is as follows:

P>0.05,accept the original hypothesis that the residuals are white noise so the fitted model is significantly valid.

3.ARMA(p,q) model test

Test the significance of the fitted model for the differential series of global air surface mean temperature change values from 1880-1985.

a<-read.table(“average_temp.txt”,header=T)

a<-ts(a[2],start=1880)

a.fit<-arima(a. order=c(1,1,1),method=”CSS”)

for(iin1:2)print(Box.test(a.fit$resial,lag=6*i))

Results are as follows:

P&gt. 0.05,accept the original hypothesis that the residuals are white noise, so the fitted model is significantly valid.

02

Significance Test of Parameters

The significance test of parameters is to test whether each unknown parameter is significantly non-zero. The purpose of this test is to make the model the most compact.

If a parameter is not significant, it means that the independent variable to which the parameter corresponds does not have a significant effect on the dependent variable, and that independent variable can be eliminated from the fitted model. The final model will be represented by a series of independent variables with significantly non-zero parameters.

The R software does not provide significant test results for the parameters, and generally outputs significantly non-zero parameters by default. If the user wants to obtain the P-value of the parameter test statistic, he needs to calculate the value of the t-statistic of the parameter and the P-value of the statistic by himself.

Call t-distribution P-value function pt can get the P-value of the t-statistic.

The pt function has the command format:

pt(t,df=,lower.tail=)

-t:value of the statistic

-df:degrees of freedom

-lower.tail: Direction for calculating probabilities

-lower.tail=T calculates Pr(X<=x) (for parametric significant tests, if the parameter estimate is negative, choose lower.tail=T)

lower.tail=F calculates Pr(X>x) (for parametric significant tests. If the parameter estimate is positive, choose lower.tail=F)

1.AR(p) model parameter test

Testing the significance of the parameters of the model fitted to the sequence of the number of miles of postal routes and rural delivery routes added per year in China from 1950 to 2008.

x<-ts(a$kilometer,start=1950)

x.fit<-arima(x,order=c(2,0,0),method=”ML”)

x.fit

The results are as follows:

#ar1 coefficient significance test

t1<-0.7185/0.1083

pt(t1,df=56,lower.tail=F)

The results are as follows.

#ar2 coefficient significance test

t2<-0.5294/0.1067

pt(t2,df=56,lower.tail=T)

The result is as follows:

#ar3 coefficient Significance test

t0=11.0223/3.0906

pt(t0,df=56,lower.tail=F)

Results are as follows:

Parametric tests show that all three coefficients are significantly non-zero, indicating that the model parameters are statistically significant.

The content of the model test of the time series is here, you have any questions can join our QQ group: biostatistics learning discussion group: 938773609. look forward to our meeting again.