71. Here is a description from Minitab of the strength data given in Exercise 13.

d1 5 x1 2 y1,

c, dn 5 xn 2 yn F 5 9

5C 1 32 sy s 2 x y 2 i 5 1, 2, x

c, n yi 5 axi 1 b x 2 m g(xg(x i 2 m)2 i 2 x)2 g(xi 2 c)2 Variable N Mean Median TrMean StDev SE Mean strength 153 135.39 135.40 135.41 4.59 0.37 Variable Minimum Maximum Q1 Q3 strength 122.20 147.70 132.95 138.25

a. Comment on any interesting features (the quartiles and fourths are virtually identical here).

b. Construct a boxplot of the data based on the quartiles, and comment on what you see.