Susan's stylist has done a great job of coloring her hair. She wants to leave a 20 percent tip. If the bill was $150, how much s
2 answers:
You might be interested in
Answer:
A sample size of 79 is needed.
Step-by-step explanation:
In a sample with a number n of people surveyed with a probability of a success of , and a confidence level of
, we have the following confidence interval of proportions.
In which
z is the zscore that has a pvalue of .
For this problem, we have that:
The margin of error is:
95% confidence level
So , z is the value of Z that has a pvalue of
, so
.
What sample size is needed if the research firm's goal is to estimate the current proportion of homes with a stay-at-home parent in which the father is the stay-at-home parent with a margin of error of 0.09?
A sample size of n is needed.
n is found when M = 0.09. So
Rounding up to the nearest whole number.
A sample size of 79 is needed.