Question

Pleas Help Me, I Dont want the answer handed to me i just want some help starting...

The mean number of matches in a particular size matchbox is 50 with a standard deviation of 2. If the number of matches per box is normally distributed, calculate the percentage of
boxes with:
(a) less than 47 matches
(b) 49 or more matches.

Answer 1

Plz dont ignore it

Answer 2

I don't remember the formulas for normal distribution. You need to find how many matchboxes fall below 1.5 standard deviation and how many above 1/2 standard deviation.

Answer 3

you have \[X\sim N(50,2^2)\] and you want to calculate
\[P(X<47)\] and \[P(X\ge49)\]

use the fact that \[\frac{X-\mu}{\sigma}\sim N(0,1)\]

Answer 4

Formula :

X < mean = 0.5-Z
X > mean = 0.5+Z
X = mean = 0.5
Z = (X-m) / σ

where,

m = Mean.
σ = Standard Deviation.
X = Normal Random Variable

Answer 5

Thanks All, Zarkon That is Perfect I Just Needed it In That Form To See How To Do It I Just Did A Load Just Like That