- Sep 20, 2003

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**UPDATE Pic as promised**

VeggieFrog was really stressed out about finals and just got a blind spot on this problem. She was shy about posting her own thread so I did it for her. Of course, it took a while and the promise of a pic to get the help she needed.

This took some doing, cause she hates how she looks in pics and doesnt like this one in particular cause she says she looks fat. This is VeggieFrog with Neosenate.

So, without further ado.. here is the pic of my beautiful daughter. ... Please be nice.. she is a nice girl.

VeggieFrog & Neosenate

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A sample of n = 100 observations from a normal distribution is drawn. The population mean is 500 and the population standard deviation is 200. Find the following:

a) P(x > 480)

b) P(460 < x < 480)

c) P(x > 530)

Now, I've got the answers but I don't understand HOW they were gained. HOW did it go from 1.0 and not 0.1?

The formula I've been given is: (x - ?) / ? ; ? is mean and ? is std dev.

This is how a) was worked out in my

(480 - 500) / 200 = -20/200 = -0.1

There is a standard normal distribution chart that you take 0.1 and get the value according to this chart, but the next step has the answer from 1.0 and not 0.1. Why did it change?

formula: it's (x - (mu) ) / (sigma)

also, the final answer is 84.13%

that's 0.5 + 0.3413 (1.0 from chart)

multiplied by 100 to make a percentage

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