# Can someone help me with my Math work ?

The weights of ice cream cartons are normally distributed with a mean weight of 11 ounces and a standard deviation of 0.5 ounce.

(a) What is the probability that a randomly selected carton has a weight greater than 11.22 ounces? Round to 4 decimal places

(b) A sample of 25 cartons is randomly selected. What is the probability that their mean weight is greater than 11.22 ounces? Round to four decimal places

### 1 Answer

- IndikosLv 74 weeks ago
a) the z-score is ( 11.22 - 11)/.5 = .44

Pr( X > .44 ) = .33

( using a normal prob calculator http://onlinestatbook.com/2/calculators/normal_dis... )

b) mean of the sample is normally with mean = 11 and std dev of .5/sqrt(25) = .1

z score = ( 11.22 - 11)/.1 = 2.2

So prob that the mean of a random sample is prob that a sttandared normal variate exceeds 2.2 = .0132