Chapter 6, Problem 81H

Thuy Dau, Ngoc Bui, Sam Su, and Lan Voung conducted a survey as to how long customers at Lucky claimed to waft in the checkout line until their turn. Let X time in line. Table 6.3 displays the ordered real data (In minutes):

Table 6.3

a. Calculate the sample mean and the sample standard deviation.

b. Construct a histogram.

c. Draw a smooth curve through the midpoints of the tops of the bars.

d. In words, describe the shape of your histogram and smooth curve.

e. Let the sample mean approximate p and the sample standard deviation approximate a. The distribution of X can then be approximated by X $\sim$________________)

f. Use the distribution in part e to calculate the probability that a person will wait fewer than 6.1 minutes.

g. Determine the cumulative relative frequency f waiting less than 6.1 minutes.

h. Why aren’t the answers to pan f and part g exactly the same?

j, Why are the answers to part f and part g as close as they are?

j. If only ten customers has been surveyed rather than 50, do you think the answers to part f and part g would have been closer together or farther apart? Explain vow conclusion.

0.50	4.25	5	6	7.25
1.75	4.25	5.25	6	7.25
2	4.25	5.25	6.25	7.25
2.25	4.25	5.5	6.25	7.75
2.25	4.5	5.5	6.5	8
2.5	4.75	5.5	6.5	8.25
2.75	4.75	5.75	6.5	9.5
3.25	4.75	5.75	6.75	9.5
3.75	5	6	6.75	9.75
3.75	5	6	6.75	10.75