Question

For a distribution with a mean of 80 and standard deviation of 10, at least what percentage of values will fall between 60 and 100 ?

Answer 1

Find the Z score of both:
Z =(X-μ)/σ

Z₁ = (60-80)/10 ==> -2

& Z₂ =(100-80)/10==>+2


& you will find on the Z score tables that the probability to be between
60 & 100 is 0.95 or 95%