91影视

The sample of drive through service times in seconds at McDonalds during dinner hours from data set 25 鈥淔ast Food鈥� in Appendix B.

The given sample data in increasing order is:

84, 119, 121, 123, 146, 152, 162, 181, 266.

In the given data, the sample size is 9. Each value is the proportion of $\frac{1}{9}$of the sample.

So, the cumulative left areas, can be expressed in general as $\frac{1}{2n},\frac{3}{2n},\frac{5}{2n},鈥�\text{and}鈥�鈥�\text{so}鈥�鈥�\text{on}$.

For the given sample size,$\text{n}=8$ , the cumulative left areas, can be expressed as

$\frac{1}{18},\frac{3}{18},\frac{5}{18},\frac{7}{18},\frac{9}{18},\frac{11}{18},\frac{13}{18},\frac{15}{18}鈥�\text{and}鈥�\frac{17}{18}$

The cumulative left areas expressed in decimal form are 0.0555, 0.1667, 0.2778, 0.3889, 0.5000, 0.6111, 0.7222, 0.8333, and 0.9444.

Refer to the standard normal distribution table, the z-score values corresponding to 0.0555, 0.1667, 0.2778, 0.3889, 0.5000, 0.6111, 0.7222, 0.8333, and 0.9444 for left-tailed areas is equal to -1.59, -0.97, -0.59, -0.28, 0.00, 0.28, 0.59, 0.97, 1.59.

Pair thesample values ofdrive-through service times at McDonald鈥檚 during dinner hours with the corresponding z-score in the form of (x, y) as:

(84,-1.59), (119, -0.97), (121, -0.59), (123, -0.28), (146, 0), (152, 0.28), (162, 0.59), (181, 0.97), (266, 1.59)

Steps to draw Normal quantile plot are as follows:

1. Make horizontal axis and vertical axis.
2. Mark the points 80, 100, 120 up to 280 on the horizontal axis and points -1.5, -1.0, -0.5, up to 1.
3. Provide title to horizontal and vertical axis as 鈥淴 values鈥� and 鈥淶-score鈥� respectively.
4. Mark the coordinates on the plot and obtain the normality plot as shown below.

From the normal quantile plot, the point shows a symmetric pattern close to linearity. So, the sample of drive through service time at McDonalds during dinner hours appears to be from a normally distributed population.