Answer:How often does Old Faithful blow?
The world's most famous geyser, Old Faithful in Yellowstone, currently erupts around 20 times a day. These eruptions are predicted with a 90 percent confidence rate, within a 10 minute variation, based on the duration and height of the previous eruption.
Step-by-step explanation:
How often does Old Faithful blow?
The world's most famous geyser, Old Faithful in Yellowstone, currently erupts around 20 times a day. These eruptions are predicted with a 90 percent confidence rate, within a 10 minute variation, based on the duration and height of the previous eruption.
Answer:

Step-by-step explanation:
Given


Required

We have:

This gives:

Open bracket

Collect like terms


Answer:
66.25 ft
Step-by-step explanation:
25.5 + 40.75
66.25
They are 66.25 feet away from each other.
Please let me know if I'm wrong!
Answer: 20
Step-by-step explanation:
We assume that the heights of boys in a high school basketball tournament are normally distributed.
Given : Mean height of boys :
inches.
Standard deviation:
inches.
Let x denotes the heights of boys in a high school basketball tournament .
Then the probability that a boy is taller than 70 inches will be :-
![P(x> 70)=1-P(x\leq70)\\\\=1-P(\dfrac{x-\mu}{\sigma}\leq\dfrac{70-70}{2.5})\\\\=1-P(z\leq0)=1-0.5=0.5\ \ \text{[by using z-value table]}](https://tex.z-dn.net/?f=P%28x%3E%2070%29%3D1-P%28x%5Cleq70%29%5C%5C%5C%5C%3D1-P%28%5Cdfrac%7Bx-%5Cmu%7D%7B%5Csigma%7D%5Cleq%5Cdfrac%7B70-70%7D%7B2.5%7D%29%5C%5C%5C%5C%3D1-P%28z%5Cleq0%29%3D1-0.5%3D0.5%5C%20%5C%20%5Ctext%7B%5Bby%20using%20z-value%20table%5D%7D)
Now, the expected number of boys in a group of 40 who are taller than 70 inches will be :-

Hence, the expected number of boys in a group of 40 who are taller than 70 inches=20