Question

Normal Distribution

The time required to finish a test is normally distributed with a mean of 60 minutes and a standard
deviation of 10 minutes. What is the probability that a student will finish the test between 50 and 60
minutes?

Answer 1

forgot all about absolute mean deviation

Answer 2

All of these questions are based on a normal (bell-shaped) distribution of data for which 68% lie within one standard deviation, 95% within two, and 99.7% within three. Considering that:
1= 100%-32% /2 = 84%
2= 68%/2 = 34%
3= 68% + (95%-68%)/2 = 81.5%

Answer 3

That is your help. You will need to use a z-Score chart which goes into the 68-96-99.7 rule further so you can evaluate exactly what percent of students get what grade given the standard deviation.

Answer 4

This literally makes no sense.