Question

a fast food restaurant sells an average of 113 cheeseburger meals a day, with a standard deviation of 14 meals. the restaurant wants to identify the days on which its sales are n the lowest 25%. there are a total of 92 days included in the analysis. what are the highest sales in the group of 25% worst ales days?

Answer 1

solution

Given that,

mean = = 113

standard deviation = = 14

n = 92

= 113

= / n = 14/92=1.46

Using standard normal table,

P(Z < z) = 25%

= P(Z < z) = 0.25

= P(Z < -0.67) = 0.25

z = -0.67 Using standard normal table,

Using z-score formula  

= z * +   

=-0.67*1.46+113

=112.02