The histographic results of steady load tests on 237 rolling-contact bearings are: Where L is the life

Question:

The histographic results of steady load tests on 237 rolling-contact bearings are:

Where L is the life in millions of revolutions and f is the number of failures. Fit a lognormal distribution to these data and plot the PDF with the histographic PDF superposed. From the lognormal distribution, estimate the life at which 10 percent of the bearings under this steady loading will have failed.

Distribution
The word "distribution" has several meanings in the financial world, most of them pertaining to the payment of assets from a fund, account, or individual security to an investor or beneficiary. Retirement account distributions are among the most...