If the center is at (0, 0) and the vertex is at (20, 0), then the distance, a, is the length from the center to the vertex, 20. The distance from the center to the focus is c. The distance from the center to the focus is 16, so c = 16. The formula we use to find the focus is
. We have our c value and our a value, so we will sub in those to find b.
and 256 = 400 - b^2. -b^2 = -144, so b = 12. There you go!
So we are given the mean and the s.d.. The mean is 100 and the sd is 15 and we are trying the select a random person who has an I.Q. of over 126. So our first step is to use our z-score equation:
z = x - mean/s.d.
where x is our I.Q. we are looking for
So we plug in our numbers and we get:
126-100/15 = 1.73333
Next we look at our z-score table for our P-value and I got 0.9582
Since we are looking for a person who has an I.Q. higher than 126, we do 1 - P. So we get
1 - 0.9582 = 0.0418
Since they are asking for the probability, we multiply our P-value by 100, and we get
0.0418 * 100 = 4.18%
And our answer is
4.18% that a randomly selected person has an I.Q. above 126
Hopes this helps!
Malik can remain honest with his partner Samuel and respect his opinion.
