A random sample of 80 college students showed that 44 had driven a car during the day before the survey was conducted. Suppose that we are interested in forming a 80 percent confidence interval for the proportion of all college students who drove a car the day before the survey was conducted. Where appropriate, express your answer as a proportion (not a percentage). Round answers to three decimal places.

The 80% confidence interval for the proportion of all college students who drove a car the day before the survey was conducted is (0.479, 0.621).

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 .

A random sample of 80 college students showed that 44 had driven a car during the day before the survey was conducted.

This means that

80% 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 80% confidence interval for the proportion of all college students who drove a car the day before the survey was conducted is (0.479, 0.621).

-362

step-by-step explanation:

(12)(4)+2(12)-34(12)+2(12)-3

  \/         \/         \/         \/

  48 +   24 -   408 + 24 - 3

      \   /               \   /

          72     -     432 - 3 = -363

114 plus 113 times 2 and 114 times 3