There is some evidence suggesting that you are likely to improve your test score

Question

There is some evidence suggesting that you are likely to improve your test score if you rethink and change answers on a multiple-choice exam (Johnston, 1975). To examine this phenomenon, a teacher gave the same final exam to two sections of a psychology course. The students in one section were told to turn in their exams immediately after finishing, without changing any of their answers. In the other section, students were encouraged to reconsider each question and to change answers whenever they felt it was appropriate. Before the final exam, the teacher had matched 9 students in the first section with 9 students in the second section based on their midterm grades. For example, a student in the no-change section with an 89 on the midterm exam was matched with student in the change section who also had an 89 on the midterm. The difference between the two final exam grades for each matched pair was computed and the data showed that the students who were allowed to change answers scoring higher by an average of MD=7 points with SS=288 .

b. Construct a 95% confidence interval to estimate the size of the population mean difference.

c. Write a sentence demonstrating how the results of the hypothesis test and the confidence interval would appear in a research report.

Explanation / Answer

here std deviation =(SS/(n-1))1/2 =6

and std error =std deviation/(n)1/2 =2

hence test stat t=(X-mean)/std error =7/2=3.5

for above p value for 8 degree of freedom =0.0081

as p vlaue is low then 0.05 level we conclude that there is significnat difference

b) for 95% CI, and 8 degree of freedom t =2.306

hence confidence interval =sample mean -/+ t*std error =2.3880 ; 11.6120

c|)as our confidence interval does not contain 0 as probable value, it also shows significant difference.

Related Questions

Navigate

• Browse (All)
• Browse T
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.