9514 1404 393
Answer:
7.6
Step-by-step explanation:
The relevant relation is ...
Cos = Adjacent/Hypotenuse
cos(51°) = x/12
x = 12·cos(51°) ≈ 7.552
x ≈ 7.6
Answer:
-20+1 every minute
Step-by-step explanation:
The confidence interval is given by

where

is the sample mean and

is the standard error of the mean. In turn, the standard error of the mean is

where

is sample size.
We have

The endpoints of the confidence interval correspond to the finite endpoints of the rejection region. That is,

for which we can solve for

. We get

which is the critical value for a confidence level of

.