References about this question: The t Test for Independent Means; The Distribution of Differences between Means; Estimating the Population Variance; Hypothesis Testing with a t Test for Independent Means; Assumptions of the t Test for Independent Means; Effect Size and Power for the t Test for Independent Means

Question: If a number of research participants take a pretest and a post-test with a mean difference score of 2.0, and if the standard deviation of the comparison distribution is .5, what is the t score?

Group of answer choices

4.0

3.0

10

.05

Question: The research design that the t-test for dependent means is associated with is sometimes called:

Separate Group

Related Group

External Difference

Repeated-Measures

It is known that a particular laboratory task takes the average person 2.5 seconds. A researcher was interested in whether older people are slower (take longer) on this task. The researcher tested 30 randomly selected 80-year-olds. Their mean time was 2.7 seconds, and you calculate ()2 (top part of the variance) to be 56.84.Use the .05 level; Use the t-test for single sample.What is the null hypothesis?

Older people and people in general are not different (including possibility that older people could be faster)

Older people and people in general are different from one-another

Older people are faster than people in general

Older people are slower than people in general

In the experiment above, what is the mean of the comparison distribution?

1.5

2.5

2.7

1.4

In the experiment above, what is the estimated population variance?

2.34

1.89

1.34

1.96

0.11

In the experiment above, what is the standard deviation of the distribution of means?

.065

1.96

.256

2.5

3.5

In the experiment above, what is the cutoff sample score?

1.699

-1.881

2.250

-1.121

1.556

In the experiment above, what is the value of t?

2.7

.781

.255

.683

.711

In the experiment above, let's say you had low power, what do you conclude?

Older people are slower than the general population on this task

Older people are faster than the general population on this task

Older people are similar to the general population on this task

We failed to show that older people are different and results are inconclusive