Question

If accrotime guarantees a full refund on any defective watch for 2 years after purchase, what percentage of total production will the company expect to replace? (round your answer to two decimal places.)

Answer 1

 The problem is missing some parts but nevertheless here is the solution:

Given:

Mean is 28

Standard deviation is 5

 

So we denote the problem as x <= 2

 For X ~ N (28, 5^2) 
we are looking for the percentage:

P{X>24} = P {Z>z}

 Where z = (24-28)/5 = 4/5 = - 0.80. 

P {Z> -0.80} = 1 - P{Z< -0.80} = 1 - 0.2119.

Or in percentage, it is replaced as P{Z< -0.80} = 0.2119, 21.19%.