The mean is 32
The median is 67
Answer:
The 80% confidence interval for the population proportion of disks which are defective is (0.059, 0.079).
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
.
Suppose a sample of 1067 floppy disks is drawn. Of these disks, 74 were defective.
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 population proportion of disks which are defective is (0.059, 0.079).
Step-by-step explanation:

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