3. Suppose that your unit has implemented a new program to improve the quality of care last year and you are interested in knowing how effective this new program by assessing the readmission rates before and after the intervention. In this case, you would want to use??

Single sample t-tests

Dependent two-sample t-tests

ANOVA tests

4. An experimenter wishes to conduct a study on the effects of exposing babies to classical music on later academic ability. She has a sample of 50 babies, some of whom are to be assigned to the experimental condition (and who will be exposed to classical music as part of the study) and some of whom are to be assigned to the control condition (and who will not be exposed to any classical music). If the experimenter wishes to maximize the power of a t test comparing the two samples, how should she allocate her sample to the two conditions?

She should assign most of the babies to the experimental condition and relatively few to the control condition.

She should assign an equal number of babies to the control condition and the experimental condition.

She should assign most of the babies to the control condition and relatively few to the experimental condition.

5.Questions 5 and 6 use the following information

Terri wants to find out whether participation in team sports changes IQ scores. She finds four pairs of students from a class, where both members of a pair got identical scores on a recent IQ test. She then takes one member from each pair and gets them to join sports teams for one semester. The other member of each pair is forbidden from joining sports teams. At the end of the semester, she tests their IQs again. Here are the results:

Which statistical test will Terri use to analyze her data?

single-sample t test.

dependent-samples t test.

Any of these tests can be used.

7. Questions 7 and 8 use the following information.

Sharon thinks that a person's desire to eat seafood will be changed after watching nature documentaries on sea creatures. She recruits ten participants; half-watch a documentary on the underwater world, whereas the other half watch a placebo documentary about the weather. Later, both groups are given a questionnaire about eating preferences, which include questions about seafood. Sharon transforms these responses into a "seafood preference scale" (varying from 0-10), where higher numbers represent a stronger desire to eat seafood. Here are the results of the scale:

Which statistical test should Sharon use to analyze her data?

single-sample t test.

matched-pairs t test.

independent-samples t test.

8. How many degrees of freedom are there in the study?

5

8

9

9. In a dependent-samples t test, we use a sampling distribution of

means of samples from the experimental population.

differences between pairs of sample means, where one sample is from the control population and one sample is from the experimental population.

raw scores.

12. In regards to ANOVA procedures, which of the following statements is true?

The sum of squares is a measure of the standard deviation of a sample.

The mean square is a measure of the standard deviation of a sample.

The mean square is a measure of the variance of a sample

14. In ANOVA, the alternative hypothesis states

there are differences between at least two of the groups in the experiment

there are differences between at least two factors in the experiment.

there are no differences between any groups in the experiment.

16.In a t test we call the weighted average variance of a set of samples the pooled variance. What do we call the weighted average variance when we compute an ANOVA?

Sum of the squared error deviations SSe

Mean of the squared error deviations MSe

Sum of the squared between-group deviations SSb

Mean of the squared between group deviations MSb

17. In ANOVA, what is the between-condition variance?

A value that is expected to be zero under the null hypothesis.

The denominator of the F ratio.

A measure of the variability between group means.

18.The F ratio is

MSb/MSw

SSw/SSb

SSb/SSw

19. In ANOVA, before we can use the sums of squared deviations, we must convert them into variance estimates by

squaring them.

dividing by the degrees of freedom.

multiplying by the degrees of freedom.

20. The degrees of freedom for SSBis given by the formula

k-1, where k is the number of groups.

N-1, where N is the number of subjects.

k-N.

21. The degrees of freedom for SSw are given by the formula

N-1, where N is the number of subjects.

N-k.

k-N.

22. The degrees of freedom for SSTare given by the formula

N-1, where N is the number of subjects.

23. In the independent-samples t test, the "pooled standard deviation" is a measure of

the average variability in the two samples

the additional variability present under the alternative hypothesis.

the variability of the largest sample.

24. In an independent-samples t test, unlike the dependent-samples t test, we DO NOT subtract individual scores in one sample from individual scores in the other sample. Why not?

The scores of one sample may be measured in a different way than the scores of the other sample.

Members of one sample have no relationship with members of the other sample.

These are all reasons that we do not subtract one score from another in the independent-samples t test.

25. The independent-samples t test uses one formula if n1 = n2 and a different formula if n1n2. What is one reason for this difference?

When n1n2 we can no longer subtract scores in one sample from matched pairs in the other sample.

We need to give more weight to the variability of the larger sample than the variability of the smaller sample.

All of the above