The amount of time it takes on an exam is normally distributed with a mean of 72 minutes and standard deviation 4 minutes. Suppose you take a random sample of 64 students from this population. There would be a 99.7% chance that the sample mean amount of time taken on the exam would be between:

A. 68 and 76 minutes
B. 71 and 73 minutes
C. 70.5 and 73.5 minutes
D. 60 and 84 minutes

Option C) 70.5 and 73.5 minutes

Step-by-step explanation:

We are given the following information in the question:

Mean, μ = 72 minutes

Standard Deviation, σ = 4 minutes

Sample size, n = 64

We are given that the distribution of amount of time is a bell shaped distribution that is a normal distribution.

Empirical Formula:

Standard error due to sampling =

Thus, by empirical formula 99.7% of data will lie between:

There would be a 99.7% chance that the sample mean amount of time taken on the exam would be between 70.5 and 73.5 minutes.

Thus, the correct answer is

Option C) 70.5 and 73.5 minutes

just do 5.2 + 2 ( 7.2) and 1/3 x 3 (.9) and youv'e got your equation. 0.9( 9/10) + 7.2 ^2 = 16.4 hope i could !

step-by-step explanation:

addition

step-by-step explanation: