Question

The average number of calories in a 1.5-ounce chocolate bar is 225. Suppose that the distribution of calories is approximately normal with s 10. Find the probability that a randomly selected chocolate bar will have a. Between 200 and 220 calories

Answer 1

Answer:

The probability that a randomly selected chocolate bar will have a. Between 200 and 220 calories will be 0.3023

Step-by-step explanation:

Given:

True mean=225

S.D=10

X1=200 and X2=220

To Find:

P(X1<x<X2)

Solution:

BY using Z-table for probability and Z-score we can proceed.

So

For 200 calories Z will be ,

Z=(sample mean -true mean)/S.D

=200-225/10

=-25/10

=-2.5

For 220 calories Z will be ,

Z=220-225/10

=-5/10

=-0.5

So required probability will be

$P(-2.5$

$=P(-2.5$

$=P(0>z>2.5)-P(0>z>0.5)$

$=0.4938-0.1915$

=0.3023