Question

Suppose that scores on a particular test are normally distributed with a mean of 110 and a standard deviation of 20. What is the minimum score needed to be in the top 2% of the scores on the test

Answer 1

Answer:

The minimum score needed to be in the top 2% of the scores on the test

is  n = 10,00,000

Step-by-step explanation:

Step(i):-

Mean of the Population = 110

Standard deviation of the Population = 20

The estimated error = 2% = 0.02

Step(ii):-

The estimated error is determined by

                        $E = \frac{S.D}{\sqrt{n} }$

                       $0.02 = \frac{20}{\sqrt{n} }$

               ⇒ $\sqrt{n} = \frac{20}{0.02} = 1000$

Squaring on both sides, we get

                   n = 10,00,000

The minimum score needed to be in the top 2% of the scores on the test

is  n = 10,00,000