Question

For sample mean x = 150, sample size n = 36 and sample standard deviation s = 40 find 80% confidence interval for population mean. population standard deviation is not known. use formula for one mean t-interval procedure in section 8.4 of etext with t-value from appendix table iv (use column t0.10). 135.6 to 148.4 154.2 to 175.8 141.3 to 158.7 162.3 to 187.5

Answer 1

The solution for this problem is:
The x-bar or the mean is = 150Confidence level is 80%sample size is 36
E = t*s/sqrt(n)= 1.3062*40/sqrt(36)=1.3062 * 6.66667= 8.708
An 80% Confidence Interval is: 150-8.708 < u < 150+8.708Or141.3 < u < 158.7 is the confidence interval