Find the point estimate of the population mean Find the marg

Find the point estimate of the population mean. Find the margin of error for a 90% confidence interval.

Determine the minimum survey size that is necessary to be 95% confident that the sample mean waking time is within 10 minutes of the population mean waking time.

135 145    95 140 135    95 110    50

90 165 110 125    80 125 130 110

25    75    65 100    60 125 115 135

95    90 140    40    75    50 130    85

100 160 135    45 135 115    75 130

Solution

7)The data that follows represents waking times of 40 people who start work at 8:00am (in minutes past 5:00am).

a)Find the point estimate of the population mean.

b)Find the margin of error for a 90% confidence interval.

c)Determine the minimum survey size that is necessary to be 95% confident that the sample mean waking time is within 10 minutes of the population mean waking time.

135 145    95 140 135    95 110    50

90 165 110 125    80 125 130 110

25    75    65 100    60 125 115 135

95    90 140    40    75    50 130    85

100 160 135    45 135 115    75 130

ANSWER

a) 103.5 minutes;

b) 9.0 minutes;

c) 47 people