Subject Post-Test Score Pre-Test Score Differences? 1 18 15 2 44 42 3 25 22 4 36
ID: 3154021 • Letter: S
Question
Subject Post-Test Score Pre-Test Score Differences?
1 18 15
2 44 42
3 25 22
4 36 34
5 47 47
6 46 45
7 44 40
8 43 33
9 34 28
10 33 28
What is the standard deviation of the difference in scores?
Question 31 options:
4.69
2.875
2.722
10
4.69
2.875
2.722
10
Explanation / Answer
sample standard deviation=sqrt(sample variance)=sqrt(8.2667)=2.8751
therefore answer is second choice=2.875
Post-test score Pre-test score differences=d d-d-=3.6 (d-d-)2 18 15 3 -0.6 0.36 44 42 2 -1.6 2.56 25 22 3 -0.6 0.36 36 34 2 -1.6 2.56 47 47 0 -3.6 12.96 46 45 1 -2.6 6.76 44 40 4 0.4 0.16 43 33 10 6.4 40.96 34 28 6 2.4 5.76 33 28 5 1.4 1.96 sum= 370 334 36 0 74.4 sample variance=sum(d-d-)/(n-1)=74.4/9= 8.266666667