Question #2f498

1 Answer
Jun 29, 2017

4773 students


If you have a graphing calculator, you can use it to find the answer!

Hit 2nd > VARS > 2: normalcdf(

This will prompt you for the lower bound, upper bound, mean (#mu#), and standard deviation (#sigma#).

First, fill in your lower and upper bounds. You want to find how many students scored between 20 and 40. Therefore,

lower bound = 20
upper bound = 40

Fill in #mu# (the mean) as 40 and #sigma# (the standard deviation) as 10 (these values are given in the question).

Then press paste and enter, and you should get an answer of approximately .4772499385. This is the percentage of students who scored between 20 and 40, but we want how many students.

Multiply the total number of students (10,000) by the percent (.477...):

#10,000 xx .4772499385 = 4772.499385#

If we round up, then about 4773 students scored between a 20 and a 40.

Hope this helps! :)