Answer:
E
Step-by-step explanation:
Solution:-
- We are to investigate the confidence interval of 95% for the population mean of walking times from Fretwell Building to the college of education building.
- The survey team took a sample of size n = 24 students and obtained the following results:
                 Sample mean ( x^ ) = 12.3 mins
                 Sample standard deviation ( s ) = 3.2 mins
- The sample taken was random and independent. We can assume normality of the sample.
- First we compute the critical value for the statistics. 
- The z-distribution is a function of two inputs as follows:
- Significance Level  ( α / 2 ) = ( 1 - CI ) / 2 = 0.05/2 = 0.025
Compute: z-critical = z_0.025 = +/- 1.96
- The confidence interval for the population mean ( u ) of  walking times is given below:
                       [ x^ - z-critical*s / √n  ,   x^ + z-critical*s / √n  ]
Answer:        [ 12.3 - 1.96*3.2 / √24  ,  12.3 + 1.96*3.2 / √24  ]