Question

The advertising department of a nationally circulated magazine wishes to estimate the mean age of its subscribers within 0.5 year with 90% confidence. If they estimate that the standard deviation of the ages of their subscribers is about 5 years, what is the minimum size of the sample they must take: Group of answer choicesa. 17 b. 165 c. 45 d. 271 e. 13

Answer 1

Answer: Option 'd' is correct.

Step-by-step explanation:

Since we have given that

Margin of error = 0.5 years

Standard deviation = 5

At 90% confidence, z = 1.645

We need to find the minimum size of the sample they must take.

So,

$n=(\dfrac{z\sigma}{E})^2\\\\n=(\dfrac{1.645\times 5}{0.5})^2\\\\n=270.6\\\\n\approx 271$

Hence, Option 'd' is correct.