Answer:
Step-by-step explanation:
20% of 30 is 6
Words: 6 Students in Ms. Martin's class did not do their homework.
hope this helps :)
Answer: 41/75 or 54.67%
Step-by-step explanation:
Buttons --- yes, zips --- yes = 45 (compute as 150 - 37 - 45 - 23)
Buttons --- yes, zips --- no = 37
Buttons --- no, zips --- yes = 45
Buttons --- no, zips --- no = 23
Therefore, 82 out of 150 bags have buttons so probability = 82/150 = 41/75
Answer:
a) 
And replacing we got:

b) ![E(80Y^2) =80[ 0^2*0.45 +1^2*0.2 +2^2*0.3 +3^2*0.05]= 148](https://tex.z-dn.net/?f=%20E%2880Y%5E2%29%20%3D80%5B%200%5E2%2A0.45%20%2B1%5E2%2A0.2%20%2B2%5E2%2A0.3%20%2B3%5E2%2A0.05%5D%3D%20148)
Step-by-step explanation:
Previous concepts
In statistics and probability analysis, the expected value "is calculated by multiplying each of the possible outcomes by the likelihood each outcome will occur and then summing all of those values".
The variance of a random variable Var(X) is the expected value of the squared deviation from the mean of X, E(X).
And the standard deviation of a random variable X is just the square root of the variance.
Solution to the problem
Part a
We have the following distribution function:
Y 0 1 2 3
P(Y) 0.45 0.2 0.3 0.05
And we can calculate the expected value with the following formula:

And replacing we got:

Part b
For this case the new expected value would be given by:

And replacing we got
![E(80Y^2) =80[ 0^2*0.45 +1^2*0.2 +2^2*0.3 +3^2*0.05]= 148](https://tex.z-dn.net/?f=%20E%2880Y%5E2%29%20%3D80%5B%200%5E2%2A0.45%20%2B1%5E2%2A0.2%20%2B2%5E2%2A0.3%20%2B3%5E2%2A0.05%5D%3D%20148)
Answer:
C)
Step-by-step explanation:
g has to be less than 7.2
The only number that fulfills this demand is C) which is 5