Refer to the data set below (body mass index of men) and determine whether the r
ID: 3258497 • Letter: R
Question
Refer to the data set below (body mass index of men) and determine whether the requirement of a normal distribution is satisfied. Assume that this requirement is loose in the sense that the population distribution need not be exactly normal, but it must be a distribution that is basically symmetric with only one mode.
33.2 24.3 23.1 27.8 25.9 27.3 21.3 26.8 32.2 28.5 19.7 26.6 20.6 26.4 25.3 30.6 24.7 26.1 23.9 23.6
Is the requirement of a normal distribution satisfied?
A. No. The points in the normal quantile plot do not lie close to a straight line.
B. Yes. The points in the normal quantile plot lie reasonably close to a straight line.
C. No. The histogram of the data is not bell shaped. There is also more than one outlier.
D. Yes. The points in the normal quantile plot exhibit some systematic pattern that is not a straight-line pattern.
Explanation / Answer
We can use MINITAB for calculating Probability plot. By use the following procedure:
Choose Graph > Probability Plot.
Choose Single, then click OK.
In Graph variables, enter Fabric.
Click Scale, then click the Percentile Lines tab
In Show percentile lines at Y values, type 87. Click OK in each dialog box.
Interpreting the results
A normal distribution with a mean of 25.83 and a standard deviation of 3.640 appears to fit your sample data fairly well. The plotted points form a reasonably straight line. The plotted points follow the fitted distribution line fairly closely.
The p-value for the Anderson-Darling test is above 0.10.
Hence , option B] is correct. that is Yes. The points in the normal quantile plot lie reasonably close to a straight line.