For sample mean x 80 sample size n 36 and sample standard

For sample mean x = 80, sample size n = 36 and sample standard deviation s = 24
find 90% confidence interval for population mean.
This is the case when population standard deviation is not known.
Use formula on page 328 with t-value.
Find t-value in Appendix Table IV.
Tip: For confidence level 90%  ? = 1 - 0.90 = 0.10, ?/2 = 0.10/2 = 0.05
So, in Table IV use column t_0.05 and line with df = n - 1 = 36 - 1 = 35.

from 65.48 to 95.86

from 75.44 to 82.16

from 73.24 to 86.76

from 70.18 to 88.65

Solution

from 75.44 to 82.16