Question

Specifications for a DVD player says that it should weight between 24 and 25 ounces. The process has a normal distribution with a mean of 24.5 ounces and a standard deviation of .25 ounces.

What percentage of parts will not meet the weight specifications? (The answer should be a percentage with two decimal places; no percentage sign).

Answer 1

Solution:

Mean µ = 24.5

Standard deviation σ = 0.25

Observation x = 25

Z = (x - µ)/σ = (25 – 24.5)/0.25 = 2.0000

Value of z from the table = 0.4772 (Screenshot is provided at the end of the answer)

Observation 25 is on the right of the mean, which is 24.5. So 0.5 – 0.4772 = 0.0228

As we have two tail, 0.0228*2 = 0.0456 = 0.0456*100 = 4.56%

So, 4.56% of parts will not meet the specifications.

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