A sample of 24 students from an introductory psychology clas

A sample of 24 students from an introductory psychology class were polled regarding the number of hours they spent studying for the last exam. If the mean is 7.1 hours and the standard deviation is 1.9 hours, compute a 95% confidence interval.

Solution

confidence interval (CI)   =x^-± Z_0.05 /n,

here x^-=7.1, =1.9,n=24

CI=7.1±1.96x1.9/sqrt(24)=7.1±0.76=(6.34, 7.86)