Question 1203226
n = 1000
m = 72 inches
sd = 2 feet * 12 = 24 inches

find:


1) the number of students whose height is more than 70 inches.


z = (70 - 72) / 24 = -2 / 24 = -.08333...
area to the right of that z-score = .5332068191.
multiply that by 1000 to get 533.2068191.
round to 533, since the number of students has to be an integer.


2) the number of students whose height will be between 6 feet and 6.5 feet..


6 feet = 72 inches.
6.5 feet = 78 inches.
the first part you did in inches because they wanted the answer in inches.
this part you can do in feet because they want the answer in feet.
the mean is 72 inchs / 12 = 6 feet
the standard deviation is 24 inches / 12 = 2 feet.


you have 2 z-scores.
the low z-score is z = (6 - 6) / 2 = 0
the high z-score is z = (6.5 - 6) / 2 = .5 / 2 = .25
area to the left of the low z-score is .5
area to the left of the high z-score is .5987062744.
area in between is .5987062744 - .5 = .0987862744.
multiply that by 1000 to get 98.7862744.
round to 99 since the number of students has to be an integer.


youo could have done both parts in inches or in feet and then converted to the appropriate measure at the end.
any one of those ways is appropriate.
just pick the method that works best for you.