It has been found that to much TV increases a childs waist size
When the child is between 29 and 53 months, for each hour of tv watched per week, wasit circumference increases by mean 0.43mm. This increase forms a normal distribution with a standard devition of 0.11mm.
a) What is the probability that the waist size of one child increases less than 0.441mm/hour of tv in this time period?
b) Consider a group of 4 people. What is the probability that the mean waist size increase of this group is less than 0.4mm/hour of tv in this time period?
So the mean is 0.43, Sigma(sd) is 0.11, and x is 0.441. (i Think so)
I need to find the z-score so - z= x-(mean)/sigma
: the z score is 0.441-0.43/0.11
z= 0.1
The area for 0.1 is = 0.5398 (sorry i made an error- focus on part 2)
However, this answer is wrong so what did i do that was wrong?
For part two, Do I use the new X value to find the z - score , then the ara, then multiply that area by 4?
Last edited by Nellen2222; 10-04-2012 at 01:35 PM.
Reply With Quote
Posting Permissions