Question

The number of pizzas consumed per month by university students is normally distributed with a mean of 11 and a standard deviation of 3.

Use Excel to answer the following questions:

A. What proportion of students consume more than 14 pizzas per month?

Probability = .158655

B. What is the probability that in a random sample of size 10, a total of more than 90 pizzas are consumed?

(Hint: What is the mean number of pizzas consumed by the sample of 10 students?)

Probability=

Answer 1

9A ) Given X : The number of Pizzas consumed per month is normally distributed $\mu$ = 11 and $\sigma$ = 3

we asked P( X > 14 ) ,

Using Excel command = 1 - NORMDIST( 14,11, 3 ,TRUE)

w get P( X > 14 ) = 0.158655

B) Here we are given n = 10 and  $\sum$ X = 90

so sample mean x bar = 9

we asked P( $\sum$ X > 90 ) which is P( x bar > 9 )

using Excel command = 1 - NORMDIST(9, 11, 3/SQRT(10), TRUE)

= 0.982493

probability  = 0.982493