[Thor4140]

Weights of 15-year old males
The mean weight of 15 year old males is 142 lbs, and the standard deviation is 12.3 lbs. If the sample of thirty six 15 year old males is selected, find the probability that the mean of the sample will be greater than 144.5 lbs. Assume the variable is normally distributed. Based on your answer would you considered the group overweight? Please show the work on how you arrived at your answer. I know the answer but need to see the work. Thanks

[Thor4140]

cmon man here is what i got so far


u=142 lbs.

o=12.3 lbs
N=36
x=144.5 lbs.

z=x-u
o/the square root of N

=144.5-142
12.3 divided by the square root of144.5
=2.5
12.3 divided by 12.02
= 2.5
1.023
=2.443
.5000-2.443 =-1.943
=1.94
.5000-.4738=.0262 or 2.6%

The correct answer is 0.1112 What am i doing wrong? Thanks

[tacomax]

(144.5 - 142) / (12.3 / 6) = 2.5 / 2.05 = 1.219

[MonkeyF0cker]

Originally Posted by tacomax

(144.5 - 142) / (12.3 / 6) = 2.5 / 2.05 = 1.219

[Thor4140]

Originally Posted by tacomax

(144.5 - 142) / (12.3 / 6) = 2.5 / 2.05 = 1.219

Tac where is the six coming from. the square root of 144.5 is 12.02. Also the answer in the book is .1112 Thanks

[MonkeyF0cker]

N = 36, Thor.

[MonkeyF0cker]

1.219 simply equals your z-score. You still need to convert it to a probability.

[twister]

This is just proof that degrees are vastly useless. I did this not less than 2 years ago for my Accounting degree, yet I can't remember at all how to do this. Sorry I can't be of any further help.

[tacomax]

I didn't give you the answer in your book, Thor, I merely corrected your mistake.

What you need to figure out how you get from 1.219 to 0.1112. That is, what exactly were you calculating when you got the answer of 1.219?

EDIT - beaten by the urine drinking monkey

[pocketlint]

Originally Posted by Thor4140

Tac where is the six coming from. the square root of 144.5 is 12.02. Also the answer in the book is .1112 Thanks

i thought the substances in my system from last night havent wore off when i first read this....

this is some funny $hit.....stat junkies....you need to grow up and get a hair cut...

[Thor4140]

Originally Posted by tacomax

I didn't give you the answer in your book, Thor, I merely corrected your mistake.

What you need to figure out how you get from 1.219 to 0.1112. That is, what exactly were you calculating when you got the answer of 1.219?

EDIT - beaten by the urine drinking monkey

sorry for that question Tac things got a little crazy over here. I appreciate all the help. Just trying to help a friend. I told her i know a spot to get this done and she didn't believe me. By the way what does this have to do with nursing? I did tell her that at BetCris Washington was just getting 3 with no juice and 3.5 everywhere else but i rather go without the hook and the plus juice. She really didn't care to much about my number problem. Go figure.