Answer:
4 hours
Step-by-step explanation:
33/11 = 3 hours
Plus 1-hour lunch break
Total is 4 hours
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).
Minimum possible number of guests is zero.
C = 60 + 15(0) = $60
Maximum possible number of guests is 100.
C = 60 + 15(100) = $1,560
That looks like Choice (d).