ch.9 post test

The sample mean of depression scores of 16 fifth graders was 4.4 with standard deviation of 8. If the population mean of this depression score is 6, what is the calculated t score for this sample?

-0.8

There is an entire family of t distributions that vary in shape according to the degrees of freedom used to estimate the standard error. However, for any given degrees of freedom, there is/are only ______ t distribution(s).

1

What is the critical t score if you are testing a one-tailed hypothesis, α level of .05 with df = 36?

1.688

In a study with 11 participants, what would be your critical t score for a one-tailed test at the .05 α level?

1.813

If s = 12 and N = 36, then estimated standard error equals to ______.

2.0

What is the critical t score if you are testing a two-tailed hypothesis with df = 44? (α level of .05)

2.015

A one-sample t test is used with a sample of 30 scores. The degrees of freedom for this t score are ______.

29

If s = 15 and the estimated standard error is 5, then the sample size must be equal to ______.

9

A teacher wants to find out whether her new method of teaching is effective or not. She decides to compare the exam grade from the current semester from the exam grade from previous semesters. She calculates her t score for the current semester to be .39. What can she conclude from this study?

She fails to reject the null hypothesis that the new method is not effective.

Which of the following study is appropriate for the one-sample t test?

Your teacher wants to know if students from your class study more than general college population.

As the sample size increases, a t distribution will look ______ the z distribution.

closer to

In SPSS, you can only test your sample mean to a score of "0."

false

The Central Limit Theorem states that any distribution of sample means will approach a normal distribution.

false

You use the t distribution instead of normal distribution when the sample size is smaller than 30.

false

The value of estimated standard error is related to the population variance and the ______.

sample size

The degrees of freedom determine the ______ the t distribution.

shape of

What is the main difference between z score and t score?

t Scores are used when the population variance is unknown.

If you have small sample size, you can conduct one-sample t-test when ______.

the population distribution is normal

All of the following statements are true about t tests EXCEPT ______.

they can be used when the population variance is known

You must always use estimated standard error for t score calculation.

true

You must know the sample size of the study to look up the critical t score.

true

If the p value from the output of SPSS is .02, then ______.

you can reject H0 if α = .05