At a constant amplitude, completely reversed bending stress level, the cycles-to-failure experience with 69 specimens of 5160H steel from 1.25-in hexagonal bar stock was as follows:

Where L is the life in thousands of cycles, and f is the class frequency of failures.
(a) Construct a histogram with class frequency f as ordinate.
(b) Estimate the mean and standard deviation of the life for the population from which the sample was drawn.

L 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 2 1 3 5 8 12 6 10 8 5 23 20 1