Question

The heights of a certain group of adult males were found to be normally distributed. The mean of the height is 170 cm with a standard deviation of 6 cm. In a group of 1,200 of these males, about how many would be more than 164 cm tall?

Answer 1

You can figure this out with the normal curve. You're interested in knowing what percentage of adult males are taller than -1 * the Standard deviation. So if you go to an area under the normal curve calculator (I use http://www.stat.berkeley.edu/~stark/Java/Html/NormHiLite.htm) you see that from -1 to 5, you get 84.13%

Answer 2

The website is: http://www.stat.berkeley.edu/~stark/Java/Html/NormHiLite.htm

Answer 3

I need the number of males. Does the website help me with that? Thank you though :)

Answer 4

well 164 is 1 standard deviation below the mean so you have the upper half(50%) and the value os 1 standard deviation below the mean 34.1%. Add the 2 percantages, divide by 100 and multiply by 1200 for the answer

so

> 164: (34.1 + 50)/100 x 1200 =

just calculate for the answer

Answer 5

Thank you!

Answer 6

so you would multiply 1200 * .8413 = 1010

Answer 7

wait.. @lionheart why would I multiply 1200 by .8413?

Answer 8

In your sample of 1200, 84.13% are above 164 cm.

Answer 9

here is a simple image showing the percentages.

and yes... thats the answer

Answer 10

Alright, thank you both of you :)