Answer:
a)
, in which z is related to the confidence level.
b) A sample size of 991 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
.
The margin of error is:

In 16% of all homes with a stay-at-home parent, the father is the stay-at-home parent
This means that 
a. 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 0.03 (round up to the next whole number).
This is n for which
. So





, in which z is related to the confidence level.
Question b:
99% confidence level,
So
, z is the value of Z that has a pvalue of
, so
.



Rounding up
A sample size of 991 is needed.
Answer:

Step-by-step explanation:
The question implies a constant rate or distribution of calories. Therefore, we can set up the following proportion:

14.38 is the awnser because you just cut the circumfrance in a weird way that would take to long to expmain, but it's 14.38.