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:
About 3 times faster
Step-by-step explanation:
Cheetah's speed = 110 km / hr
World 100m sprint record :
Speed of sprinter :
Distance / time
100 m / 9.58s
= 10.438413 m/s
Convert Cheetah's speed to m/s
110 km/hr = (110 * 1000)m / (60 * 60 s)
= 110000 m / 3600 s
= 30.55555 m/s
Number of times cheetah is faster than sprinter :
30.55555 m/s ÷ 10.438413 m/s
= 2.927 times
Answer:
0x+2y=22
Step-by-step explanation:
Set them equal to each other, (5x+4y=25)-(5x+2y=3). Distribute the negative into the right equation, (5x+4y=25)(-5x-2y=-3). Then combine like terms to get your answer.
Answer:
13,200 feet
Step-by-step explanation:
There are 5280 feet in a mile, so multiply 5280 by 2.5
5280*2.5=13,200
So, every Wednesday, she runs 13,200 feet
Hope this helps! :)
