Answer: A: 0.0031
Step-by-step explanation:
Given : In a study of wait times at an amusement park, the most popular roller coaster has a mean wait time of 17.4 minutes with a standard deviation of 5.2 minutes.
i.e. 
and 
We assume that the wait times are normally distributed.
samples size : n= 30
Let x denotes the sample mean wait time.
Then, the probability that the mean wait time is greater than 20 minutes will be :
![P(x>20)=1-P(x\leq20)\\\\=1-P(\dfrac{x-\mu}{\dfrac{\sigma}{\sqrt{n}}}\leq\dfrac{20-17.4}{\dfrac{5.2}{\sqrt{30}}})\\\\=1-P(z\leq2.74)\ \ [\because\ z=\dfrac{x-\mu}{\dfrac{\sigma}{\sqrt{n}}}]\\\\=1-0.9969\ \ [\text{ By z table}]\\\\=0.0031](https://tex.z-dn.net/?f=P%28x%3E20%29%3D1-P%28x%5Cleq20%29%5C%5C%5C%5C%3D1-P%28%5Cdfrac%7Bx-%5Cmu%7D%7B%5Cdfrac%7B%5Csigma%7D%7B%5Csqrt%7Bn%7D%7D%7D%5Cleq%5Cdfrac%7B20-17.4%7D%7B%5Cdfrac%7B5.2%7D%7B%5Csqrt%7B30%7D%7D%7D%29%5C%5C%5C%5C%3D1-P%28z%5Cleq2.74%29%5C%20%5C%20%5B%5Cbecause%5C%20z%3D%5Cdfrac%7Bx-%5Cmu%7D%7B%5Cdfrac%7B%5Csigma%7D%7B%5Csqrt%7Bn%7D%7D%7D%5D%5C%5C%5C%5C%3D1-0.9969%5C%20%5C%20%5B%5Ctext%7B%20By%20z%20table%7D%5D%5C%5C%5C%5C%3D0.0031)
Hence, the probability that the mean wait time is greater than 20 minutes.= 0.0031
Thus , the correct answer is A: 0.0031 .
Answer:
More sod is needed
Step-by-step explanation:
Well we know that 3/4 of a bag of sod covers 55 ft^2 then if we divide 55 by 3 we get 18.3333 we take that and multiply by 4 to get 73.333 or the amount one bag of sod can cover
73.333*3 cuz 3 bags of sod is 220 ft^2
She needs more sod
Answer:
192,000
Step-by-step explanation:
480,000x.40 = 192,000 commission.
None of the above. The correct expansion is
.
Answer:
HI is 8 as the equal angles resemble equilateral triangle
rhe angle is 110 as the two equal sides represent isosceles triangle
Step-by-step explanation:
hope it helped!!!
