you can play around with Z-table stuff at
http://davidmlane.com/hyperstat/z_table.html
A manufacturer knows that their items have a normally distributed lifespan, with a mean of 5.6 years, and standard deviation of 1.6 years.
If 25 items are picked at random, 1% of the time their mean life will be less than how many years?
Give your answer to one decimal place.
2 answers
from a z-score table
1% of the population is approx. 2.33 s.d. below the mean
2.33 * 1.6 = ?
1% of the population is approx. 2.33 s.d. below the mean
2.33 * 1.6 = ?
0 answers