Question

3. Scores of 12 randomly selected exams in a statistic class are given below: 98 78 90 70 80 55 78 77 70 80 78 86 (a) (6 points) Find the mean and standard deviation. Round your answer to a whole number. It has been reported that the mean score of all statistics exams is below 80. Test the validity of the report at a = 0.02 by using the data given above. (b) (4 points) Clearly state H, and Hi, and identify the claim and type of test. H, H: (c) (4 points) Find the computed test statistic and the p-value. C.T.S.: p-Value: (d) (3 points) Use non-statistical terminology to state your final conclusion about the claim. d)

Answer 1

1² 74906 mean Score of al statistic enams is 3. n-12 El pe =940 The mean ( 2 ) = n = quo = 178.333 =(78 (a) Standard deviation Safety (22² (222) s-S174906—(94012 = 10.7563 = 11 (6) Ho: M=80 H 12 Maso @ CTS=ă-l (78-80%=-0.6298 P- values 0.2708 (P-valuce >x=0.02 level) (0) Dlusion Fail to reject to Final Conclusion. There is sufficient evidence to reject the claim that below 8o , (SG) (14) afah