Alice2005

December 28th 2005, 12:18 PM

Hello Everyone.

After consulting 5 different sources, (online sources as well as textbooks) I have come across an inconsistancy.

(This is a question regarding the standard normal distribution)

What is the percentage of the area covered by two standard deviations of the mean. Or What is P( mean + or - 2(standard deivation)). A few sources say that the answer is 95% while others say it is 96%.

When I calculate it, I get a .9544

However in doing a problem, I assumed P(-2<z<2)= 95% and got the problem completely wrong.

Please help, for I do not know

After consulting 5 different sources, (online sources as well as textbooks) I have come across an inconsistancy.

(This is a question regarding the standard normal distribution)

What is the percentage of the area covered by two standard deviations of the mean. Or What is P( mean + or - 2(standard deivation)). A few sources say that the answer is 95% while others say it is 96%.

When I calculate it, I get a .9544

However in doing a problem, I assumed P(-2<z<2)= 95% and got the problem completely wrong.

Please help, for I do not know