Here is the question

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

This is what I have 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



_____________

Here is the question

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

This is what I have 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



_____________


Your value for Z should be:

Z = 1.2195122 = (144.5 - 142) / (12.3 / Sqrt[36]).

Your value for Z should be:

Z = 1.2195122 = (144.5 - 142) / (12.3 / Sqrt[36]).

thanku :tup: