It is estimated that 80% of all eighteen-year old women have weights ranging from 103.5 to 144.5

Question:

It is estimated that 80% of all eighteen-year old women have weights ranging from 103.5 to 144.5 lb. Assuming the weight distribution can be adequately modeled by a normal curve and that 103.5 and 144.5 are equidistant from the average weight μ, calculate σ.

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...