In: Statistics and Probability
We draw a random sample of size 49 from a normal population with variance 2.1. If the sample mean is 21.5, what is a 99% confidence interval for the population mean?
Solution :
Given that,
Sample size = n = 49
Z/2
= 2.576
Margin of error = E = Z/2*
(
/
n)
= 2.576 * (1.4491 /
49)
Margin of error = E = 0.5
At 99% confidence interval estimate of the population mean is,
- E <
<
+ E
21.5 - 0.5 <
< 21.5 + 0.5
21 <
< 22
(21 , 22)