Question

With a known population mean of 1500,and a known standard error of the mean world of 42.50, what is the probability of selecting at random a sample whose mean is equal to 1450 or less.

Answer 1

Solution:

Given that,

= 1500

= 42.50

(    1450 )

=p ( - /)   (1450 - 1500 / 42.50)

= p( z   - 50 / 42.50 )

= p ( z - 1.18 )   

Using z table

= 0.1190

Probability = 0.1190