((7 + 5)^2) / (4 * 3 + 9) =
(12^2) / (12 + 9) =
144 / 21 reduces to 48/7 or 6 6/7
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



Take 1960 as 0 then find out next year's
- 1970=10
- 1980=20
- 1990=30
- 2000=40
- 2005=45
- 2010=50
Also
Divide each population by one thousand i.e turn to decimal .
This we done to create the plot on graph easily
The graph has been attached
for the below points
- (0,9.706)
- (10,10.652)
- (20,10.798)
- (30,10.847)
- (40,11.353)
- (45,11.478)
- (50,11.576)
18 / 2 = 9 || 9 x 3 = 27. Therefore, 27 students are registered in Bob’s class.
Answer:
X = 3
Step-by-step explanation:
(3-2)(3+10)
(1)(13) =
13