Question

In a certain ASU classroom, the weight of men is an average of 175 pounds, with a standard deviation of 20 pounds. Assuming a normal distribution, approximately what percent of men in the class weigh between 135 and 215 pounds

Answer 1

Answer:

99.8%

Step-by-step explanation:

Normal Distribution

Standard deviation  σ

mean  equal to 175 pounds

We should remember approximately values for intervals:

[μ  - σ/2  :  μ  + σ/2] values spread 1σ up and down mean equal to  68.3 %

[μ  -  σ  :  μ  +  σ ] values spread 2σ up and down mean equal to 95.7 %

and finally

[μ  - 1.5 σ  :  μ  + 1.5 σ ]   values spread 3σ up and down mean equal to 99.7

In our case we were asked porcentage between 4σ (40 kg) spread about mean

175 + 40  = 215

175 - 40  = 135

For that interval we should get 99.8%  of values