Question

Please consider the following information:

Sample mean (M) = 65

Population mean (µ) = µM = 61

Sample standard deviation (s) = 8

Sample size (N) = 25

Based on this information, please compute the corresponding 95% confidence interval.

Please type the lower boundary of the confidence interval as your answer. Please include at least three decimal places in your answer, if relevant.

Answer 1

df = 25 - 1 = 24

T score for 95% confidence interval = t_24,0.025 = 2.064

Confidence interval = (M + t_24,0.025 * s / sqrt(n))

                                = (65 + 2.064 * 8 / sqrt(25))

                                = (65 + 3.3024)

                                = (61.6976 , 68.3024)

Lower boundary = 61.6976