Slope = (y2 - y1)/(x2 - x1) = (-1 - 17)/(-8 - (-10)) = -18/(-8 + 10) = -18/2 = -9
Complete Question
A recent CBS News survey reported that 64% of adults felt the U.S. Treasury should continue making pennies. Suppose we select a sample of 18 adults.
a-1. How many of the 18 would we expect to indicate that the Treasury should continue making pennies
a-2) What is the standard deviation?
a-3) What is the likelihood that exactly 3 adults would indicate the Treasury should continue making pennies?
Answer:
a-1 
a-2 
a-3 
Step-by-step explanation:
From the question we are told that
The sample size is 
The proportion of adult that felt the U.S. Treasury should continue making pennies is p = 0.64
The proportion of adult that feel otherwise is

The mean is mathematically evaluated as

substituting values


The standard deviation is mathematically represented as

substituting values


The likelihood that 3 adult would indicate the Treasury should continue making pennies is mathematically evaluated as

Now
![\left n} \atop \right. C_3 = \frac{n! }{[n-3] ! 3!}](https://tex.z-dn.net/?f=%5Cleft%20%20n%7D%20%5Catop%20%20%5Cright.%20C_3%20%3D%20%20%5Cfrac%7Bn%21%20%7D%7B%5Bn-3%5D%20%21%203%21%7D)
substituting values
![\left n} \atop \right. C_3 = \frac{18! }{[15] ! 3!}](https://tex.z-dn.net/?f=%5Cleft%20%20n%7D%20%5Catop%20%20%5Cright.%20C_3%20%3D%20%20%5Cfrac%7B18%21%20%7D%7B%5B15%5D%20%21%203%21%7D)
![\left n} \atop \right. C_3 = \frac{18 * 17 * 16 * 15! }{[15] ! (3 *2 *1 )}](https://tex.z-dn.net/?f=%5Cleft%20%20n%7D%20%5Catop%20%20%5Cright.%20C_3%20%3D%20%20%5Cfrac%7B18%20%2A%2017%20%2A%2016%20%2A%2015%21%20%7D%7B%5B15%5D%20%21%20%283%20%2A2%20%2A1%20%29%7D)

So
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:
<em>BY using Z-table for probability and Z-score we can proceed.</em>
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




=0.3023