Need help answering these 7 problems! thanks 1. a repeated measures study produc

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Need help answering these 7 problems! thanks

1. a repeated measures study produces a sample mean difference of Md=4.5 with SS=2400 for a sample of n=25 individuals. based on this information, what is the value of cohen's d?

a. d=4.5/100=.045

b. d=4.5

c.d=4.5/10=.45

d.d=4.5/2=2.25

2. A research report describing the results from a repeated measures study states, the data showed a significant difference between treatments, t(22)=4.71,p<.01. From this report you can conclude that the outcome of the hypothesis test was

a. to fail to reject the null hypothesis

b. to make a type I error

c. to reject the null hypothesis

d. to make a type II error

3. a group of participants is measured before and after a treatment in a repeated-measures study. if the treatment has a consistent effect on all of the participants, then the difference scores should show

a. a large variance

b. a large mea difference

c. a small variance

d. a small mean difference

4. a major concern with a repeated-measures study is the possibility of

a. order effects

b. obtaining a mean difference that is due to individual differences rather than treatment differences

c. all of these options are major concerns

d. negative values for the difference scores

5. What is the value of the estimated standard error for the following set of D scores?

a. 1

b.12

c.2

d.4

6. For a repeated measures study with a sample of n=25 partici[ants, a researcher obtains MD=6 with a variance of s2=8 for the difference scores. If the researcher uses a confidence interval to estimate the size of the treatment effect, what value will be in the center of the interval?

a. impossible to determine without knowing the percentage of confidence

b.0

c.8

d.6

7. As the variance of the difference scores increaes, the likelihood of rejectiing the null hypothesis _____ and measurs of effect size such as r2 or cohen's d __________

a. decrease, decrease

b. increase, decrease

c. increase, increase

d. decrease, increase

Explanation / Answer

1. sample mean difference Md = 4.5 and SS = 2400 here df is 24, so statndard deviation = square root (2400/24) = 10 So d = 4.5/sd = 4.5/10 = 0.45, correct option is c) d = 0.45

2. a significant difference between treatments, t22= 4.71,   p < 0.01. Here P-value is less than the given level of significant alpha = 0.01. In such case we generally reject the null hypothesis at alpha = 0.01, So option c) is correct answer.

3. if the treatment has a consistent effect on all of the participants, then the difference scores should show a small mean difference because the individual differences are removed, the D scores are usually much less variable than the original scores. Again, a smaller variance will produce a smaller standard error, which will increase the likelihood of a significant t statistic. The treatment difference is very consistent, the D scores are all clustered close together will produce a very small value for S2. This means that the standard error in the bottom of the t statistic will be very small.

Here the correct option is c) a small variance.

4. a major concern with a repeated-measures study is the possibility of order effects, obtaining a mean difference that is due to individual differences rather than treatment differences and negative values for the difference scores. So correct option is c) all of these options are major concerns

5. What is the value of the estimated standard error for the following set of D scores?

SE = standard deviation/ square root ( n ) = 10/5 = 2, so option c) is correct answer.

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