Answer: 5.37
Step-by-step explanation:
Let x = ACT scores.
Given: ACT scores have a mean of 20.8 and 9 percent of the scores are above 28. The scores have a distribution that is approximately normal.
i.e. P(X>28)=0.09 (i)
Now,
![P(X>28)=P(\dfrac{X-\mu}{\sigma}>\dfrac{28-20.8}{\sigma})\\\\= P(z>\dfrac{7.2}{\sigma})\ \ \ \ [z=\dfrac{X-\mu}{\sigma}]](https://tex.z-dn.net/?f=P%28X%3E28%29%3DP%28%5Cdfrac%7BX-%5Cmu%7D%7B%5Csigma%7D%3E%5Cdfrac%7B28-20.8%7D%7B%5Csigma%7D%29%5C%5C%5C%5C%3D%20P%28z%3E%5Cdfrac%7B7.2%7D%7B%5Csigma%7D%29%5C%20%5C%20%5C%20%5C%20%5Bz%3D%5Cdfrac%7BX-%5Cmu%7D%7B%5Csigma%7D%5D)
(ii)
One -tailed z value for p-value of 0.09 =1.3408 [By z-table]
From (i) and (ii)
Hence, the standard deviation = 5.37
Answer:
A. 1÷(X+1) (x-2)
some steps are directly
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Answer:
The answer is 0.60b + 0.30w = 150; 60 + 0.30w = 150
Step-by-step explanation:
Wei can purchase 300 balloons.
The model used for the problem is .
Step-by-step explanation:
Let the number of white balloons = x
The cost of blue balloons and white balloons are 60 cent = $0.6 and 30 cents = $0.3 respectively.
Wei purchased 100 blue balloons and have $150 to buy both balloons
Answer:
85
Step-by-step explanation:
10x13=130, 9x5=45, 130-45=85
