Answer:
11
Step-by-step explanation:
The mean is calculated as
mean = ![\frac{sum}{count}](https://tex.z-dn.net/?f=%5Cfrac%7Bsum%7D%7Bcount%7D)
let the third number be x , then
= 15 ( multiply both sides by 3 to clear the fraction )
34 + x = 45 ( subtract 34 from both sides )
x = 11 ← third number
Answer:
Subtractionproperty of inequality.
Step-by-step explanation:
Answer:
a) 40.13% probability that a laptop computer can be assembled at this plant in a period of time of less than 19.5 hours.
b) 34.13% probability that a laptop computer can be assembled at this plant in a period of time between 20 hours and 22 hours.
Step-by-step explanation:
When the distribution is normal, we use 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 question:
![\mu = 20, \sigma = 2](https://tex.z-dn.net/?f=%5Cmu%20%3D%2020%2C%20%5Csigma%20%3D%202)
a)Less than 19.5 hours?
This is the pvalue of Z when X = 19.5. So
![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{19.5 - 20}{2}](https://tex.z-dn.net/?f=Z%20%3D%20%5Cfrac%7B19.5%20-%2020%7D%7B2%7D)
![Z = -0.25](https://tex.z-dn.net/?f=Z%20%3D%20-0.25)
has a pvalue of 0.4013.
40.13% probability that a laptop computer can be assembled at this plant in a period of time of less than 19.5 hours.
b)Between 20 hours and 22 hours?
This is the pvalue of Z when X = 22 subtracted by the pvalue of Z when X = 20. So
X = 22
![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{22 - 20}{2}](https://tex.z-dn.net/?f=Z%20%3D%20%5Cfrac%7B22%20-%2020%7D%7B2%7D)
![Z = 1](https://tex.z-dn.net/?f=Z%20%3D%201)
has a pvalue of 0.8413
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 - 20}{2}](https://tex.z-dn.net/?f=Z%20%3D%20%5Cfrac%7B20%20-%2020%7D%7B2%7D)
![Z = 0](https://tex.z-dn.net/?f=Z%20%3D%200)
has a pvalue of 0.5
0.8413 - 0.5 = 0.3413
34.13% probability that a laptop computer can be assembled at this plant in a period of time between 20 hours and 22 hours.
(8/9) / 6 =
8/9 * 1/6 =
8/54 which reduces to 4/27 of the book each day <===