# Project #16742 - Stats

Question 1

Do students tend to improve their SAT mathematics (SAT-M) score the second time they take the test? A random sample of four students who took the test twice received the following scores.

 Student 1 2 3 4 First Score 450 520 720 600 Second Score 440 600 720 630

Assuming that the change in SAT-M score (second score - first score) for the population of all students taking the test twice is normally distributed with mean µ, are we convinced that retaking the test improves scores? Find the P-value for a test of
versus .

a. State the hypothesis and the null hypothesis above in plain English.

b. Calculate a paired sample t-test and report the results.

c. Do you accept or reject the null hypothesis? Why or why not?

d. Are your results statistically significant?

 n Mean or proportion SD SE T Probability df Equal or Unequal Variance Assumed? Accept or Reject Null? Reject

Question 2

A sample of 25 students from advanced high school math class yielded a mean grade point average of 2.89 the standard deviation of grade points was 0.65. The state will give the department additional resources for funding if the class grade point average is not statistically different from 3.5.  Will the program get the additional funding based on your findings?

a. State the hypothesis and null hypothesis in both equation form and in plain English.

b. Perform a one-sample t-test and report the results.

c. What is the standard error for the sample?

c. Do you accept or reject the null hypothesis? Why?

d. Will the program get the additional funding?

 n Mean or proportion SD SE T Probability df Equal or Unequal Variance Assumed? Accept or Reject Null?

Question 3

A researcher was interested in understanding the stress levels of board members in large corporations during supplier negotiations. In one study she took a group of 8 directors and measured their anxiety (out of 15) during a normal supplier meeting and then again in another meeting in which she had paid a bogus supplier to be deliberately uncooperative. Based on the SPSS output below, how would you interpret these results?

Part I: Multiple Choice

_____a. Anxiety levels were significantly lower in meetings in which suppliers were uncooperative.

_____b. There were no significant differences between anxiety levels in normal meetings and in those in which suppliers were uncooperative.

_____c. Anxiety levels were significantly higher in meetings in which suppliers were uncooperative.

_____d. We can’t tell any of the above from the output given.

Explain why you chose the answer above based on the output.  Your answer should include a discussion of the t-statistic, the df and the significance of t.

Question 4

A researcher was interested in the effects of emotion-evoking music on exam performance. Before their SPSS exam, a lecturer took one group of students to a room in which calming music was being played. A different group of students were taken to another room in which the ‘death march’ was being played. The students then did the exam and their marks were noted. The SPSS output is below. The experimenter made no predictions about which form of support would produce the best exam performance. What should he report?

Part I: Multiple Choice

_____a. Students receiving positive music before the exam did significantly better than those receiving negative music, t(df=38) = 2.05,  p < .05.

_____b. Marks for students receiving positive music before the exam did not significantly differ from students receiving negative music, t(df=38) = 2.05,  not significant.

_____c. Students receiving positive music before the exam did significantly better than those receiving negative music, t(df=23.12) = 2.05,  p < .05, one-tailed.

_____d. Marks for students receiving positive music before the exam did not significantly differ from students receiving negative music, t(df=23.12) = 2.05,  not significant.

Explain the reasons for choosing your answer based on the SPSS output in terms of the t-statistic and any relevant measures of significance.

 Subject Mathematics Due By (Pacific Time) 11/13/2013 12:00 am
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