Question

In: Statistics and Probability

Suppose a poll of 20 voters is taken in a large city. The purpose is to...

Suppose a poll of 20 voters is taken in a large city. The purpose is to determine x, the number who favor a certain candidate for mayor. Suppose that 40% of all the city’s voters favor the candidate.

a. Find the mean and standard deviation of x.

b. What is the probability that x <=10.

c. Find the probability that x > 12.

d. Find the probability that x = 11

e. Graph the probability distribution of x.

Solutions

Expert Solution

Solution: We are given:

a. Find the mean and standard deviation of x.

Answer: The mean and standard deviation of x is:

b. What is the probability that x <=10.

Answer: We have to find:

  

c. Find the probability that x > 12.

Answer: We have to find:

d. Find the probability that x = 11

Answer: We have to find

e. Graph the probability distribution of x.

Answer: The probability distribution of x is given below:

x P(x)
0 0.00004
1 0.00049
2 0.00309
3 0.01235
4 0.03499
5 0.07465
6 0.12441
7 0.16588
8 0.17971
9 0.15974
10 0.11714
11 0.0710
12 0.03550
13 0.01456
14 0.00485
15 0.00129
16 0.00027
17 0.00004
18 0.00000
19 0.00000
20 0.00000

The graph of the probability distribution of x is:


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