There are two ways of calculating the variance in statistics (for what I studied: test hypothesis,...
There are two ways of calculating the variance in statistics (for what I studied: test hypothesis, anova, chi square, regression):
• the sum of ((Xi-X)^2 n)/N
• the sum of Xi^2 n/N and -X^2
My question is: as they give slightly different results, do I have to use a precise formula in some exercises and the other in other specifics?
Homework Answers
There are two ways of calculating the variance of a population
If data is discrete 
,
The same can be written as
which is derived from the above by expanding the summation.
Both the formullas will give you same result.
However,
The varaince of sample of size n is given by
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There are two ways of calculating the variance in statistics
(for what I studied: test hypothesis,...
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I'm not too sure what the question is asking for when calculating for S, we need...
I'm not too sure what the question is asking for when
calculating for S, we need to use MatLab for writing the script. If
anybody could be of some assistance, I need the script, and the
sample output to match
8. Let n be the number of elements in a data set and let x denote an individual element, for i 1,2,. .. , n. The mean /u and standard deviation s are given by ηΣ α-(ΣΗ ) n(n -...
2. This week, we studied the test score Y versus number of hours, X, spent on test preparation, of a student in a French class of 10 students with the collected results shown below Number of hours s...
2. This week, we studied the test score Y versus number of hours, X, spent on test preparation, of a student in a French class of 10 students with the collected results shown below Number of hours studied Test score 31 10 14 73 37 12 60 91 21 84 17 (a) Use linear normal regression analysis method or the least-squares approximation method to predict the average test score of a student who studied 12 hours for the test (b)...
Hypothesis test 9 Review of hypothesis tests 9.1 Exercise 1 Let Y be the fuel consumption...
Hypothesis test
9 Review of hypothesis tests 9.1 Exercise 1 Let Y be the fuel consumption needed for heating in a building (in decalitres) and X be the average outside daily temperature. Assuming that the sample data led to the following results: 10 10 10 10 i=1 i=1 i-1 1. find the sample mean and test the null hypothesis that the average fuel consumption is the same as last year's, which was 18 decalitres (1-α-0.95). 2. comment on the regression...
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I have to conduct a Hypothesis Test on my sample Size. sample size=58 (the first process...
I have to conduct a Hypothesis Test on my sample Size. sample size=58 (the first process involved 40 expenses and the second process was 18 expenses) I need to conduct a hypothsis test on this evaluation. •Confidence Interval: Before Improvement •X=40 •N=58 •p=40/58=0.68 •Confidence Interval: After the improvement •X=18 •N=58 •P=18/58=0.31 •Confidence Interval: (0.191, 0.429) •95% confidence (1.96)that the interval contains the true population proportion. With a Margin of error:1 • •Before the Improvement: • •Sample Standard Deviation, s 48.908185591827...
# 3. The following code draws a sample of size $n=30$ from a chi-square distribution with...
# 3. The following code draws a sample of size $n=30$ from a chi-square distribution with 15 degrees of freedom, and then puts $B=200$ bootstrap samples into a matrix M. After that, the 'apply' function is used to calculate the median of each bootstrap sample, giving a bootstrap sample of 200 medians. "{r} set.seed (117888) data=rchisq(30,15) M=matrix(rep(0,30*200), byrow=T, ncol=30) for (i in 1:200 M[i,]=sample(data, 30, replace=T) bootstrapmedians=apply(M,1,median) (3a) Use the 'var' command to calculate the variance of the bootstrapped medians....
Question Completion Status QUESTION 4 Anova: Single Factor SUMMARY Groups Count Sum Average Variance A 4...
Question Completion Status QUESTION 4 Anova: Single Factor SUMMARY Groups Count Sum Average Variance A 4 108 27 32.66666667 B 4 96 24 13.33333333 4 120 30 56 ANOVA Source of Variation SS df F crit MS P-value F Treatments 72 36 1.058823529 0.386396621 4.256494729 Error 306 9 34 Total 378 11 Based on the Results above of Single Factor ANOVA: the MSTR O 36 O 378 O 72 O 34 Click Save and Submit to save and submit. Chick...
For expert using R , I solve it but i need to figure out what I...
For expert using R , I solve it but i need to figure out what
I got is correct or wrong. Thank you
# Simple Linear Regression and Polynomial Regression
# HW 2
#
# Read data from csv file
data <-
read.csv("C:\data\SweetPotatoFirmness.csv",header=TRUE,
sep=",")
head(data)
str(data)
# scatterplot of independent and dependent variables
plot(data$pectin,data$firmness,xlab="Pectin,
%",ylab="Firmness")
par(mfrow = c(2, 2)) # Split the plotting panel into a 2 x 2
grid
model <- lm(firmness ~ pectin , data=data)
summary(model)
anova(model)
plot(model)...
Eliza Annunziato a G O A 39% D Fri 1:09 PM AutoSaver l ab12_lastname Insert Draw...
Eliza Annunziato a G O A 39% D Fri 1:09 PM AutoSaver l ab12_lastname Insert Draw Design Layout References Mailings Review Calibri (Bo... " 11 A A Aav Ą E E E BIVab x x ALLA >> Com Share A Styles e Sensitivity 346.237 000 ANOVA Model Sum of Squares df Mean Square Regression 2446.108 1 2 446.108 Residual 11904.246 1685 7.065 14350 354 1686 a. Dependent Variable: EDUC Highest year of school completed b. Predictors: (Constant), PAEDUC Highest year...
I'm not too sure what the question is asking for when
calculating for S, we need to use MatLab for writing the script. If
anybody could be of some assistance, I need the script, and the
sample output to match
8. Let n be the number of elements in a data set and let x denote an individual element, for i 1,2,. .. , n. The mean /u and standard deviation s are given by ηΣ α-(ΣΗ ) n(n -...
2. This week, we studied the test score Y versus number of hours, X, spent on test preparation, of a student in a French class of 10 students with the collected results shown below Number of hours studied Test score 31 10 14 73 37 12 60 91 21 84 17 (a) Use linear normal regression analysis method or the least-squares approximation method to predict the average test score of a student who studied 12 hours for the test (b)...
Hypothesis test
9 Review of hypothesis tests 9.1 Exercise 1 Let Y be the fuel consumption needed for heating in a building (in decalitres) and X be the average outside daily temperature. Assuming that the sample data led to the following results: 10 10 10 10 i=1 i=1 i-1 1. find the sample mean and test the null hypothesis that the average fuel consumption is the same as last year's, which was 18 decalitres (1-α-0.95). 2. comment on the regression...
i-1i0 (Two Choices: (a) or (b)) 1. One may decrease the power of a hypothesis test by increasing the sample size n. True (b) False 2, The Central Limit Theorem even applies to a sample meany from a population with a uniform distribution. (a) True (b) False 3. If events A, B, and Care all mutually-independent, then P(A u B u C) P(A) + P(B) + P(C (a) True (b) False 4. For any data set, at least half of...
# 3. The following code draws a sample of size $n=30$ from a chi-square distribution with 15 degrees of freedom, and then puts $B=200$ bootstrap samples into a matrix M. After that, the 'apply' function is used to calculate the median of each bootstrap sample, giving a bootstrap sample of 200 medians. "{r} set.seed (117888) data=rchisq(30,15) M=matrix(rep(0,30*200), byrow=T, ncol=30) for (i in 1:200 M[i,]=sample(data, 30, replace=T) bootstrapmedians=apply(M,1,median) (3a) Use the 'var' command to calculate the variance of the bootstrapped medians....
Question Completion Status QUESTION 4 Anova: Single Factor SUMMARY Groups Count Sum Average Variance A 4 108 27 32.66666667 B 4 96 24 13.33333333 4 120 30 56 ANOVA Source of Variation SS df F crit MS P-value F Treatments 72 36 1.058823529 0.386396621 4.256494729 Error 306 9 34 Total 378 11 Based on the Results above of Single Factor ANOVA: the MSTR O 36 O 378 O 72 O 34 Click Save and Submit to save and submit. Chick...
For expert using R , I solve it but i need to figure out what
I got is correct or wrong. Thank you
# Simple Linear Regression and Polynomial Regression
# HW 2
#
# Read data from csv file
data <-
read.csv("C:\data\SweetPotatoFirmness.csv",header=TRUE,
sep=",")
head(data)
str(data)
# scatterplot of independent and dependent variables
plot(data$pectin,data$firmness,xlab="Pectin,
%",ylab="Firmness")
par(mfrow = c(2, 2)) # Split the plotting panel into a 2 x 2
grid
model <- lm(firmness ~ pectin , data=data)
summary(model)
anova(model)
plot(model)...
Eliza Annunziato a G O A 39% D Fri 1:09 PM AutoSaver l ab12_lastname Insert Draw Design Layout References Mailings Review Calibri (Bo... " 11 A A Aav Ą E E E BIVab x x ALLA >> Com Share A Styles e Sensitivity 346.237 000 ANOVA Model Sum of Squares df Mean Square Regression 2446.108 1 2 446.108 Residual 11904.246 1685 7.065 14350 354 1686 a. Dependent Variable: EDUC Highest year of school completed b. Predictors: (Constant), PAEDUC Highest year...
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