Answer:
The 95% confidence interval for the percent of all black adults who would welcome a white person into their families is (0.8222, 0.8978).
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:
323 blacks, 86% of blacks said that they would welcome a white person into their families. This means that
95% confidence level
So , z is the value of Z that has a pvalue of
, so
.
The lower limit of this interval is:
The upper limit of this interval is:
The 95% confidence interval for the percent of all black adults who would welcome a white person into their families is (0.8222, 0.8978).