In: Statistics and Probability
A university department is deciding which of the research proposals to support. Eight members of staff were asked to read the proposals and to award each of them a mark out of 100. Following are the marks awarded to the proposals.
Staff | Proposal 1 | Proposal 2 |
1 | 53 | 75 |
2 | 46 | 67 |
3 | 60 | 69 |
4 | 53 | 51 |
5 | 66 | 76 |
6 | 59 | 59 |
7 | 52 | 65 |
8 | 67 | 68 |
Determine a 95% confidence interval for the difference in the mean marks awarded to the two proposals.
since sample subject is used in both groups, we will use paired t test |
for 95% CI; and 7 degree of freedom, value of t= | 2.365 | |
therefore confidence interval=sample mean -/+ t*std error | ||
margin of errror =t*std error= | 7.712195 | |
lower confidence limit = | -16.96 | |
upper confidence limit = | -1.54 | |
from above 95% confidence interval for mean difference in the mean marks awarded =(-16.96 to -1.54) |