Step-by-step explanation:
(-)(-) = +
Answer:
Step-by-step explanation:
The 99% confidence interval for the true mean is given by:
where:
is the sample mean = 69.7
is the standard deviation = 2.8
is the test statistics = 2.58 for for 99% confidentce interval.
n is the sample size = 772.
Therefore, the 99% confidence interval is: