Question 1

The quantity ó2 can best be estimated by combining,or pooling,the variance estimates from the two samples to obtain a pooled variance estimate.

Accepted Answer

A) True 
 B)False

Question 2

The degrees of freedom associated with independent Groups t-test is_________.

Accepted Answer

The answer of The degrees of freedom associated with independent...

Question 3

When researchers fail to present the value of eta squared in a manuscript,this information can still be derived by the reader based on the observed t value and the degrees of freedom.

Accepted Answer

A) True 
 B)False

Question 4

If the sample size is different in the treatment and control groups then weighted variances should be used.

Accepted Answer

A) True 
 B)False

Question 5

Confidence intervals are used to_____.

Accepted Answer

A) provide information about sampling error 
B) whether of nor a relationship exist between the independent and dependent variables 
C) whether or not homogeneity of variance has been violated. 
D) Both a & b 
E) All of these

Question 6

In practice,we typically know the values of _____,but we do not know the values of _____.

Accepted Answer

A) n1 and n2;ó12 and ó22 
B) the sample means;n1 and n2 
C) n1 and n2;the sample means 
D) ó12 and ó22;n1 and n2

Question 7

What would the value of eta-squared be if and independent t-test yielded an observed t value of -1.73 and the number of subjects in the placebo group was 10 and the number of subjects in the treatment group was 10.

Accepted Answer

A) .142 
B) .132 
C) .266 
D) None of these

Question 8

For a nondirectional alternative hypothesis it is written as H1: ì1 ? ì2.

Accepted Answer

A) True 
 B)False

Question 9

How do we determine what the nature of the relationship is between two variables?

Accepted Answer

The answer of How do we determine what the nature...

Question 10

Given the following information,find eta2.t = 2.5,n1 = 20,n2 = 18

Accepted Answer

A) .06 
B) .13 
C) .15 
D) .26

Question 11

Dr.Johnson is studying the effects of aspirin on heart rate.He believes that aspirin will lower heart rate.He has 2 groups the treatment group receives 80mg of aspirin for a week (n=4)the control group received a placebo (n=4)and their heart rates are compared.Below is his data in which heart rate is beats per minute.He sets his alpha level at 0.05 and uses a directional test. 
What is the t-value for the data above?

Accepted Answer

A) 4.20 
B) 4.19 
C) 3.91 
D) None of these

Question 12

If the researcher suspects that the strength of the relationship between two variables in the population is .20,what sample size should she use per group in a study involving two independent groups and an alpha level of .05,nondirectional test,in order to achieve a power of .75?

Accepted Answer

A) 11 
B) 13 
C) 15 
D) 17

Question 13

The degrees of freedom for the independent groups t test are equal to:

Accepted Answer

A) n1 - n2 + 2 
B) n1 + n2 - 2 
C) n1 - n2 - 2 
D) n1 + n2 + 2

Question 14

Eta2 is

Accepted Answer

A) the proportion of unexplained variance relative to the total variance. 
B) the proportion of error variance relative to the total variance. 
C) the proportion of explained variance relative to the total variance. 
D) the total amount of variability in the independent variable.

Question 15

In an independent groups t test,the null hypothesis is H0: ì1 = ì2.

Accepted Answer

A) True 
 B)False

Question 16

The standard deviation of the sampling distribution of the difference between two independent means is called the standard error of the difference between two independent means or,more simply,the standard error of the difference.

Accepted Answer

A) True 
 B)False

Question 17

The mean of the sampling distribution of the difference between two independent means is _____ to the difference between the population means for the groups in question.

Accepted Answer

A) always equal 
B) sometimes equal 
C) never equal 
D) none of these

Question 18

Given the following information,find eta2.SSTOTAL = 653,SSERROR = 405,SSEXPLAINED = 248.

Accepted Answer

A) .38 
B) .61 
C) .62 
D) 653

Question 19

Which of the following indices measures the strength of the relationship between the independent and dependent variables?

Accepted Answer

A) standard error of difference 
B) power 
C) eta2 
D) alpha

Question 20

The independent groups t test is typically used to analyze the relationship between two variables when:

Accepted Answer

A) the independent variable is quantitative in nature and is measured on a level that at least approximates interval characteristics 
B) the independent variable is between-subjects in nature 
C) the independent variable has two and only two levels 
D) all of these

Exam 10: Independent Groups T-Test

The quantity ó² can best be estimated by combining,or pooling,the variance estimates from the two samples to obtain a pooled variance estimate.

The degrees of freedom associated with independent Groups t-test is_________.

When researchers fail to present the value of eta squared in a manuscript,this information can still be derived by the reader based on the observed t value and the degrees of freedom.

If the sample size is different in the treatment and control groups then weighted variances should be used.

Confidence intervals are used to_____.

In practice,we typically know the values of _,but we do not know the values of _.

What would the value of eta-squared be if and independent t-test yielded an observed t value of -1.73 and the number of subjects in the placebo group was 10 and the number of subjects in the treatment group was 10.

For a nondirectional alternative hypothesis it is written as H₁: ì₁ ? ì_2.

How do we determine what the nature of the relationship is between two variables?

Given the following information,find eta².t = 2.5,n₁ = 20,n₂ = 18

If the researcher suspects that the strength of the relationship between two variables in the population is .20,what sample size should she use per group in a study involving two independent groups and an alpha level of .05,nondirectional test,in order to achieve a power of .75?

The degrees of freedom for the independent groups t test are equal to:

Eta² is

In an independent groups t test,the null hypothesis is H₀: ì₁ = ì₂.

The standard deviation of the sampling distribution of the difference between two independent means is called the standard error of the difference between two independent means or,more simply,the standard error of the difference.

The mean of the sampling distribution of the difference between two independent means is _____ to the difference between the population means for the groups in question.

Given the following information,find eta².SS_TOTAL= 653,SS_ERROR= 405,SS_EXPLAINED= 248.

Which of the following indices measures the strength of the relationship between the independent and dependent variables?

The independent groups t test is typically used to analyze the relationship between two variables when: