Question 1150922
a. In what percent of the days are there {{{8}}} or fewer customers returning items?


{{{z(8) = (8-10.3)/2.25 = -1.0222}}}

%({{{x<=8}}} )= %({{{z<=-1.0222}}}) = {{{15.33}}}%


b. In what percent of the days are between {{{12}}} and {{{14}}} customers returning items?

{{{Normalcdf(12,14,10.3,2.25)}}} = {{{17.49}}}%


c. Is there any chance of a day with no returns?

{{{z(0) = (0-10.3)/2.25}}} = {{{-4.5778}}}

%({{{x<=0 }}})= %({{{z<=-4.5778}}}) = {{{0.00023518}}}%