Question

Determine the sample size required to estimate the mean score on a standardized test within 2 points of the true mean with 99% confidence. Assume that s = 13 based on earlier studies
The sample size required is?

Answer 1

Answer:

280

Step-by-step explanation:

Margin of error = critical value × standard error

Here, the margin of error is 2.

At 99% confidence, the critical value is z = 2.576.

The standard error is s / √n = 13 / √n.

2 = 2.576 (13 / √n)

2 = 33.49 / √n

√n = 16.74

n = 280.4

Rounded to the nearest person, the required sample size is 280.