# Normal Distribution

#2 If you are grading the class according to your z score in a normal distribution. would you rather have a score of 70 in class A where the mean is 55 and the standard deviation is 10, or a score of 80 in class B where the mean is 60 and standard deviation is 15? What would the percentile rank be in class A and B and what does it mean to you. How would you rank a score of 50% in A and B? What would be the area under the curve between a score of 50 and 57 in class A.

#3 Nationally the population for black people is .13. In a class there are two black people out of 23.

A) What is the proportion of black people in the class?

B) Increase the class(sample) size from 23 to 230. Is the proportion in the class (see a) SIGNIFICANTLY LOWER THAN THE NATIONAL Proportion? Use alpha =.05

https://brainmass.com/statistics/normal-distribution/normal-distribution-5702

#### Solution Summary

The solution uses Normal Distribution for

1) deciding which is a better score: a score of 70 in class A where the mean is 55 and the standard deviation is 10, or a score of 80 in class B where the mean is 60 and standard deviation is 15

2) tests a hypothesis