Question

The average weight of a professional football player in 2009 was 246.2 pounds. Assume the population standard deviation is 25 pounds. A random sample of 32 professional football players was selected. Complete parts a through e.

a. Calculate the standard error of the mean.

b. What is the probability that the sample mean will be less than 234 pounds?

Answer 1

Solution :

Given that ,

mean = = 246.2

standard deviation = = 25

n = 32

a) =   = 246.2

= / n = 25 / 32 = 4.42

b) P( < 234 ) = P(( - ) / < (234 - 246.2) /4.42 )

= P(z < -2.76)

Using z table

= 0.0029