Question

An instructor believes that students do not retain as much information from a lecture on a Friday compared to a Monday. To test this belief, the instructor teaches a small sample of college students some preselected material from a single topic on statistics on a Friday and on a Monday. All students received a test on the material. The differences in scores for material taught on Friday minus Monday are listed in the following table.

Difference Scores
(Friday − Monday)

+3.3

+4.3

+6.4

+1.1

−1.5

(a) Find the confidence limits at a 95% CI for these related samples. (Round your answers to two decimal places.)
to

(b) Can we conclude that students retained more of the material taught in the Friday class?

Yes, because 0 lies outside of the 95% CI. No, because 0 is contained within the 95% CI.

Answer 1

a)

sample mean         x=	2.720
sample size             n=	5.000
sample std deviation s=	3.033
std error sx=s/√n=	1.3566

for 95% CI; and 4 df, critical t=		2.7760
margin of error E=t*std error                            =		3.766
lower bound=sample mean-E =		-1.05
Upper bound=sample mean+E=		6.49
from above 95% confidence interval for population mean =(-1.05,6.49)

b)

No, because 0 is contained within the 95% CI.