Question

The weights of ice cream cartons are normally distributed with a mean weight of 20 ounces and a standard deviation of 0.5 ounces. You randomly select 25 cartons. What is the probability that their mean weight is greater than 20.06 ounces?

0.274

0.452

0.726

0.548

Answer 1

Solution :

Given that,

mean = = 20

standard deviation = = 0.5

n = 25

= 20

₌ / n = 0.5 25 = 0.1

P ( >20.06 )

= 1 - P ( < 20.06)

= 1 - P ( - / ) < ( 20.06 - 20/0.1)

= 1 - P ( z < 0.06/ 0.1 )

= 1 - P ( z < 0.6)

Using z table

= 1 -0.2743

= 0.7257

Probability = 0.7257

Option 0.726 is correct.