Question

A fast food restaurant would like to know the number of customers it serves on drive through window during peak hours.The store manager randomly selects 32 different customers driving on the drive through and records each customer. For this sample, X-bar equal 95 and s2=230.

Answer 1

As we are trying to see the number of customers it serves on drive through window during peak hours, we can do this by obtaining a 95% confidence interval for the same.

As we are not give the distribution as normal and we are not given the population standard deviation, we will use the t distribution tables to obtain the confidence interval here.

For n - 1 = 31 degrees of freedom, we have from the t distribution tables here:
P( t31 < 2.040) = 0.975

Therefore, due to symmetry we get here:
P( -2.040 < t31 < 2.040) = 0.95

The confidence interval thus is obtained here as:

Therefore with 95% confidence level, we can say that from 89 to 101 customers are served on an average.