Normal Distributions Use Table

• 99.04%

• 0.96%

• 98.93%

• 97.68%

How is the graph distributed?

• Approximately Normal

• Skewed to the Left

• Skewed to the Right

• Uniform

According to the empirical rule, what percentage of data falls within 1 standard deviation? 

• 25%

• 68%

• 95%

• 99.7%

​ The monthly income of 5000 workers at the Microsoft plant are distributed normally. Suppose the mean monthly income is $1250 and the standard deviation is $250.

Creating a normal distribution curve shows that the percentage of workers who earn less than $1750 per month is ​ (a)  

• 800 workers

• 125 workers

• 81.5% of workers

• 97.5% of workers

The monthly income of 5000 workers at the Microsoft plant are distributed normally. Suppose the mean monthly income is $1250 and the standard deviation is $250.
Creating a normal distribution curve shows that the percentage of workers who earn between $750 and $1500 per month is ​ (a)  

• 800 workers

• 125 workers

• 81.5% of workers

• 97.5% of workers

A grading scale is set up for 1000 students' test scores. It is assumed the scores are normally distributed with a mean score of 75 and a standard deviation of 15.

If a grade of a 60 is the lowest passing score, how many students are expected to pass the test? ​ (a)  

How many students are expected to fail the test? ​ (b)  

• 840 students

• 160 students

• 84 students

• 16 students

• 877 students

• 123 students

​ The monthly income of 5000 workers at the Microsoft plant are distributed normally. Suppose the mean monthly income is $1250 and the standard deviation is $250.

Creating a normal distribution curve shows that the amount of workers who earn more than $1500 per month is ​ (a)  

• 800 workers

• 125 workers

• 81.5% of workers

• 97.5% of workers

​ The monthly income of 5000 workers at the Microsoft plant are distributed normally. Suppose the mean monthly income is $1250 and the standard deviation is $250.

Creating a normal distribution curve shows that the amount of workers who earn less than $750 per month is ​ (a)  

• 800 workers

• 125 workers

• 81.5% of workers

• 97.5% of workers

The green normal distribution curve has a standard deviation of 20. Does the purple normal distribution curve have a standard deviation that is larger or smaller than 20?​ (a)  

• larger

• smaller

The area under a normal distribution between z = –2 and z = 1 is

• ≈ 68%

• ≈ 82%

• ≈ 95%

• ≈ 97%