(21 + 34 + x + 25 + 37 + 22) / 6 = 30
(139 + x) / 6 = 30 .....multiply both sides by 6
139 + x = 30 * 6
139 + x = 180
x = 180 - 139
x = 41......so during week 3, she rode her bike 41 miles
Answer: 2x-1
combine like terms: 4x and -2x
-4 and 3
Answer:71.4
Step-by-step explanation:140*51%
Answer and Explanation:
Given : The random variable x has the following probability distribution.
To find :
a. Is this probability distribution valid? Explain and list the requirements for a valid probability distribution.
b. Calculate the expected value of x.
c. Calculate the variance of x.
d. Calculate the standard deviation of x.
Solution :
First we create the table as per requirements,
x P(x) xP(x) x² x²P(x)
0 0.25 0 0 0
1 0.20 0.20 1 0.20
2 0.15 0.3 4 0.6
3 0.30 0.9 9 2.7
4 0.10 0.4 16 1.6
∑P(x)=1 ∑xP(x)=1.8 ∑x²P(x)=5.1
a) To determine that table shows a probability distribution we add up all five probabilities if the sum is 1 then it is a valid distribution.


Yes it is a probability distribution.
b) The expected value of x is defined as

c) The variance of x is defined as

d) The standard deviation of x is defined as



The table is linear because the change because it had a constant slope when we solve for change in y / change in x for each of the data points given. That slope is -0.5 and it’s constant.