The answer is A.
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The answer is (D) hope the is helps
Answer:
B. 
Step-by-step explanation:
![\displaystyle x^2 = -8x - 7 → x^2 + 8x + 7 \\ \\ x^2 + 8x + 7 \\ [x + 1][x + 7]; -1, -7 = x](https://tex.z-dn.net/?f=%5Cdisplaystyle%20x%5E2%20%3D%20-8x%20-%207%20%E2%86%92%20x%5E2%20%2B%208x%20%2B%207%20%5C%5C%20%5C%5C%20x%5E2%20%2B%208x%20%2B%207%20%5C%5C%20%5Bx%20%2B%201%5D%5Bx%20%2B%207%5D%3B%20-1%2C%20-7%20%3D%20x)
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Answer:
68% of jazz CDs play between 45 and 59 minutes.
Step-by-step explanation:
<u>The correct question is:</u> The playing time X of jazz CDs has the normal distribution with mean 52 and standard deviation 7; N(52, 7).
According to the 68-95-99.7 rule, what percentage of jazz CDs play between 45 and 59 minutes?
Let X = <u>playing time of jazz CDs</u>
SO, X ~ Normal(
)
The z-score probability distribution for the normal distribution is given by;
Z =
~ N(0,1)
Now, according to the 68-95-99.7 rule, it is stated that;
- 68% of the data values lie within one standard deviation points from the mean.
- 95% of the data values lie within two standard deviation points from the mean.
- 99.7% of the data values lie within three standard deviation points from the mean.
Here, we have to find the percentage of jazz CDs play between 45 and 59 minutes;
For 45 minutes, z-score is =
= -1
For 59 minutes, z-score is =
= 1
This means that our data values lie within 1 standard deviation points, so it is stated that 68% of jazz CDs play between 45 and 59 minutes.