stat and research
posted by anna on .
3. A researcher is interested in whether listening to music helps or hinders testperformance. To control for differences in cognitive level, this researcher decides to use a withinparticipants design. He selects a random sample of participants and has them study different material of equal difficulty in both the music and no music conditions. Participants take a 20item quiz on the material. The table below shows the scores on the quiz. The study is completely counterbalanced to control for order effects. The scores obtained are measured on an intervalratio scale and are normally distributed.
Music No Music
17 17
16 18
15 17
16 17
18 19
18 18
a. What statistical test should be used to analyze the data?
b. Is this a one or two tailed test?
c. Identify H0 and Ha for this study.
d. Conduct the appropriate analysis. Should H0 be rejected? What should the researcher conclude?
e. Calculate the 95 confidence interval.

C. Identify H0 and Ha for this study.

It would help to use the same name.
"whether listening to music helps or hinders testperformance"
Ho: mean music = mean no music
Ha: mean music ≠ mean no music
How many tails would that have?
Find the mean first = sum of scores/number of scores
Subtract each of the scores from the mean and square each difference. Find the sum of these squares. Divide that by the number of scores to get variance.
Standard deviation = square root of variance
Z = (mean1  mean2)/standard error (SE) of difference between means
SEdiff = √(SEmean1^2 + SEmean2^2)
SEm = SD/√n
If only one SD is provided, you can use just that to determine SEdiff.
Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion related to your Z score.
I'll let you do the calculations.