Question

In a nationwide survey conducted by a reputable research​ center, a sample of adults in a certain country were asked whether they favor a plan to break up a small collection of​ megabanks, which controlled about ​% of the banking​ industry; ​% of those sampled responded in the affirmative. According to the​ report, "the margin of sampling error is ​/ percentage points with a ​% level of​ confidence." Find and interpret a ​% confidence interval for the percentage of all adults in the country who favor a plan to break up the megabanks.

Answer 1

Answer:

(42% ; 48%)

We are 99% confident that the percentage of all adults in the country who favor a plan to break up the megabanks is between 42% and 48%

Step-by-step explanation:

The confidence interval is used to estimate the range of values for which the population value may lie at a certain level of confidence.

Given that :

Phat = 45%

Margin of error = ±3%

The confidence interval is defined as :

C. I = Phat ± margin of error

C. I = 45% ± 3%

Lower boundary :

45% - 3% = 42%

Upper boundary :

45% + 3% = 48%

C.I = (42% ; 48%)

We are 99% confident that the percentage of all adults in the country who favor a plan to break up the megabanks is between 42% and 48%