Question

Suppose we have a dataset called MYDATA. There are two variables: COMPANY and SALARY. The variable COMPANY consists of CO1, CO2, and CO3 and the variable SALARY includes the employees’ salaries from these three companies. Which code is most appropriate SAS code to run ANOVA?

PROC UNIVARIATE DATA = MYDATA;

VAR COMPANY SALARY;

PROC UNIVARIATE DATA = MYDATA;

VAR COMPANY;

PROC GLM DATA=MYDATA;

CLASS COMPANY;

MODEL SALARY = COMPANY;

PROC GLM DATA=MYDATA;

CLASS COMPANY;

MODEL COMPANY = SALARY;

Consider the following completely randomized experimental design with one independent variable, i.e., dietary intervention to reduce body weight (dependent variable). Twenty volunteers were randomly divided into four groups of five; each group was then randomly assigned to one of the following four treatments:

Treatment 1 - control

Treatment 2 - diet

Treatment 3 - physical activity

Treatment 4 - diet plus physical activity

The test statistic has the F distribution with how many degrees of freedom?

20 - 1 = 19

4 - 1 = 3 and 20 - 4 = 16

20 - 4 and 4 - 1 = 3

4 - 1 = 3

Question 3 1 pts

In ANOVA, does the p-value indicate which pair(s) of means are significantly different?

No, it doesn’t.

No, but yes when the p-value is smaller than the significance level.

Yes, it does.

Yes, but no when the p-value is greater than the significance level.

Question 4 1 pts

You are conducting ANOVA and obtained the F statistic of 3.56. The sample size is 10 with 4 treatment. What is the p-value for this test? Use this website to calculate.

http://onlinestatbook.com/2/calculators/F_dist.html (Links to an external site.)Links to an external site.

0.047

0.1163

0.1624

0.0869

Question 5 1 pts

Which R function can perform ANOVA?

ANOVA

aov

Anova

AOV

Question 6 1 pts

In ANOVA, what is the general interpretation of “rejecting the null hypothesis”?

All means are significantly different.

At least one pair of means is significantly different.

All means are same.

All of these are correct.

Question 7 1 pts

A study was conducted to determine if the mean performance score is higher among men than women. An appropriate test is _________.

one sample t-test

independent t-test

paired t-test

ANOVA

Question 8 1 pts

In ANOVA, can we have a different number of people assigned to each treatment group?

Yes, but only when the variabilities are same.

No

It depends on one study to another.

Yes

Question 9 1 pts

Examine the R code and output below.

CompA<-c(1, 3, 5, 3, 4, 3, 4, 5, 5, 2, 3, 3, 1, 3, 5)

CompB<-c(2, 3, 4, 4, 3, 3, 3, 1, 2, 4, 2, 3)

t.test(CompA, CompB, alternative="two.sided")

Welch Two Sample t-test

data: CompA and CompB

t = 1.1356, df = 24.613, p-value = 0.2671

alternative hypothesis: true difference in means is not equal to 0

95 percent confidence interval:

-0.407546 1.407546

sample estimates:

mean of x mean of y

3.333333 2.833333

What is the underlying research hypothesis?

The means from CompA and CompB are different.

The means from CompA and CompB are the same.

The means from CompA are higher than that of CompB.

The means from CompA are lower than that of CompB.

Question 10 1 pts

What does the acronym ANOVA stand for?

Analysis of variance and statistics

Analysis of variance

Analysis of variability

Analysis on variance

Answer 1

1.

PROC GLM DATA=MYDATA;

CLASS COMPANY;

MODEL SALARY = COMPANY;

2. Moving on to an ANOVA with four groups. We know the answer if this is a one-way ANOVA (that is, a 4 x 1 design): df1 = k – 1 = 4 -1 = 3.

3. No, but yes when the p-value is smaller than the significance level.

4. p-value for this test 0.047

5. aov

6. All means are same.

7. ANOVA

8. In ANOVA, can we have a different number of people assigned to each treatment group? Yes, but only when the variabilities are same as In one-way ANOVA is that very unequal sample sizes can affect the homogeneity of variance assumption.

9. The means from CompA and CompB are different.

10. Anova stands for Analysis of Variance