Answer:
There is an 84% probability that your standard refrigerator will last between 12 and 20 years.
Step-by-step explanation:
Problems of normally distributed samples can be solved using the z-score formula.
In a set with mean
and standard deviation
, the zscore of a measure X is given by:
![Z = \frac{X - \mu}{\sigma}](https://tex.z-dn.net/?f=Z%20%3D%20%5Cfrac%7BX%20-%20%5Cmu%7D%7B%5Csigma%7D)
The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.
In this problem, we have that:
A standard refrigerator's mean life expectancy is 18 years with a standard deviation of 2 years. This means that
.
What is the probability that your standard refrigerator will last between 12 and 20 years?
This probability is the pvalue of Z when
subtracted by the pvalue of Z when
. So
X = 20
![Z = \frac{X - \mu}{\sigma}](https://tex.z-dn.net/?f=Z%20%3D%20%5Cfrac%7BX%20-%20%5Cmu%7D%7B%5Csigma%7D)
![Z = \frac{20 - 18}{2}](https://tex.z-dn.net/?f=Z%20%3D%20%5Cfrac%7B20%20-%2018%7D%7B2%7D)
![Z = 1](https://tex.z-dn.net/?f=Z%20%3D%201)
has a pvalue of 0.8413
X = 12
![Z = \frac{X - \mu}{\sigma}](https://tex.z-dn.net/?f=Z%20%3D%20%5Cfrac%7BX%20-%20%5Cmu%7D%7B%5Csigma%7D)
![Z = \frac{12- 18}{2}](https://tex.z-dn.net/?f=Z%20%3D%20%5Cfrac%7B12-%2018%7D%7B2%7D)
![Z = -3](https://tex.z-dn.net/?f=Z%20%3D%20-3)
has a pvalue of 0.0014
This means that there is a 0.8413-0.0014 = 0.8399 = 0.84 = 84% probability that your standard refrigerator will last between 12 and 20 years.
List the hours from 1 to 8
Multiply the hours by how much she is paid per hour ( $12)
X: 1, 2, 3, 4, 5, 6, 7, 8
y: 12, 24, 36, 48, 60, 72, 84, 96
Answer:
-4
Step-by-step explanation:
Use the slope formula to find the slope m.
m = −4
HOPE THIS HELPS :)
Answer:
24
Step-by-step explanation:
4xy
4(2)(3)
24