Question

The university is interested in estimating the average time students spend online in a Canvas class at any one time. They wish to estimate this average time to within 2 minutes at the 99% reliability level. Prior sampling indicates that the standard deviation for the amount of time spent online at any one time is 20 minutes. How large a sample should the university select?

Group of answer choices

n=34

n=541

n=385

n=664

Answer 1

Solution :

Given that,

standard deviation = = 20

margin of error = E = 2

At 909% confidence level the z is ,

   = 1 - 99% = 1 - 0.99= 0.01

/ 2 = 0.01 / 2 = 0.005

Z_/2 = Z_0.005 = 2.576

Sample size = n = ((Z_/2 * ) / E)²

= ((2.576 * 20) /2 )²

= 664

Sample size = n = 664

Option 4th