Answer:
34.5%
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, we have that:
![\mu = 9, \sigma = 2.5](https://tex.z-dn.net/?f=%5Cmu%20%3D%209%2C%20%5Csigma%20%3D%202.5)
What percentage of the books last more than 10 years?
As a proportion, this is 1 subtracted by the pvalue of Z when X = 10. 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{10 - 9}{2.5}](https://tex.z-dn.net/?f=Z%20%3D%20%5Cfrac%7B10%20-%209%7D%7B2.5%7D)
![Z = 0.4](https://tex.z-dn.net/?f=Z%20%3D%200.4)
has a pvalue of 0.655
1 - 0.655 = 0.345
So
34.5% of the books last more than 10 years.
Answer:
10.7cm
Step-by-step explanation:
x^2= 115
x = √115
x = 10.7
The answer is 41. Hope this helps!
Answer:
7/12 ≈ 0.583
Step-by-step explanation:
See picture below. There are 21 totals higher than 6 out of 36 possible outcomes. The probability is therefore 21/36 = 7/12.
How do you write The difference between 7 and the product 3x is 23
3x -7 =23