An electrical firm manufactures a 100-watt light bulb, which, according to specifications written on the package, has

Question:

An electrical firm manufactures a 100-watt light bulb, which, according to specifications written on the package, has a mean life of 900 hours with a standard deviation of 50 hours. At most, what percentage of the bulbs fails to last even 700 hours? Assume that the is symmetric about the mean.
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...