Answer:
![E(X) = 4*0.2 +3*0.5+ 2*0.2 +1*0.8+ 0*0.02= 2.78](https://tex.z-dn.net/?f=%20E%28X%29%20%3D%204%2A0.2%20%2B3%2A0.5%2B%202%2A0.2%20%2B1%2A0.8%2B%200%2A0.02%3D%202.78)
So then the best answer for this case would be:
C. 2.78
Step-by-step explanation:
For this case we have the following probabability distribution function given:
Score P(X)
A= 4.0 0.2
B= 3.0 0.5
C= 2.0 0.2
D= 1.0 0.08
F= 0.0 0.02
______________
Total 1.00
The expected value of a random variable X is the n-th moment about zero of a probability density function f(x) if X is continuous, or the weighted average for a discrete probability distribution, if X is discrete.
If we use the definition of expected value given by:
![E(X) = \sum_{i=1}^n X_i P(X_I)](https://tex.z-dn.net/?f=%20E%28X%29%20%3D%20%5Csum_%7Bi%3D1%7D%5En%20X_i%20P%28X_I%29)
And if we replace the values that we have we got:
![E(X) = 4*0.2 +3*0.5+ 2*0.2 +1*0.8+ 0*0.02= 2.78](https://tex.z-dn.net/?f=%20E%28X%29%20%3D%204%2A0.2%20%2B3%2A0.5%2B%202%2A0.2%20%2B1%2A0.8%2B%200%2A0.02%3D%202.78)
So then the best answer for this case would be:
C. 2.78
Answer:
Option A is true
The researchers proved that exercise causes weight loss only for high school students.
Step-by-step explanation:
We are told that the researchers found a high correlation, 0.93, between amount of exercise and weight lost.
Now, looking at each of the options;
- A is True because due to the high correlation, the research proves that exercise causes weight loss but only for high school students.
- B is not true because we are told the correlation is very high at 0.93. Thus, it is untrue that there is no proven causation.
-C is not true because there's no where that the researchers have completely proved that exercise causes weight loss generally. It is only peculiar to the high school students studied.
-D is not true because the 93% is just a correlation and not a percentage of those who lost weight
Answer:
21/4 :3/4= 21/4 *4/3= 7/1 *1/1 = 7
7 bookcases
Step-by-step explanation:
A= 16777216
B= 279936
C= 32768
D= 49
Answer:
1130.97 (last option)
Step-by-step explanation:
Basically its the circumference times 12. Circumference of the circle is 2 * 15 * pi which is 30 pi. 30pi * 12 is 360pi which is around 1130.97 or the last option