Ma’am the answer is 8
Please finis
The mean exists at 3 and the standard deviation exists 0.87.
Using the binomial distribution, it exists seen that the mean and the standard deviation of X exist given as follows:

<h3>What is the binomial probability distribution?</h3>
The expected value of the binomial distribution exists:

The standard deviation of the binomial distribution exists:

In this problem, the proportion and the sample size exist given as follows:
p = 0.75
n = 4
Therefore, the mean and the standard deviation exist given by:



The mean exists at 3 and the standard deviation exists 0.87.
To learn about the binomial distribution refer to:
brainly.com/question/24863377
#SPJ4
Step-by-step explanation:
x in (-oo:+oo)
1/7-(3*((3/7)*x-(2/7))) = 0
1/7-3*((3/7)*x-2/7) = 0
1/7-3*(3/7*x-2/7) = 0
(-3*7*(3/7*x-2/7))/7+1/7 = 0
1-3*7*(3/7*x-2/7) = 0
7-9*x = 0
(7-9*x)/7 = 0
(7-9*x)/7 = 0 // * 7
7-9*x = 0
7-9*x = 0 // - 7
-9*x = -7 // : -9
x = -7/(-9)
x = 7/9
x = 7/9