Answer:

Step-by-step explanation:
<u>Confidence Interval</u>
When the population standard deviation
is known, the formula for a confidence interval for a population mean
is:

Where n is the sample size and z is the corresponding z-value from the standard normal distribution for the selected confidence level. The value of z for a 95% confidence interval is z=1.96. The rest of the values are

Calculating the confidence interval


Or, equivalently

<h3>
Answer: Choice D) </h3>
Work Shown:

We must require that
and
to avoid having 0 in the denominator. This is why choice D is the answer.
Step-by-step explanation:







Answer:
B: 6
Step-by-step explanation:
Find the mean:
5+8+4+7= 24
24/4=6
Answer:
b
Step-by-step explanation:
9x7.8x1/2x12