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#1
if you know that The arithmetic mean of the heights of a group of people is 172 and standard deviation is 6 What is the percentage of people whose height ranges between 162 and 178?
one supposed it can be solved without using Z table!!
 

Dason

Ambassador to the humans
#2
If you assume a normal distribution then look up the empirical rule. If not then search Chebyshevs inequality