Assignment
Problem 2
The popularity rate of a political candidate is 62%. If 18 citizens are randomly selected, what is the probability that at least 11 in the sample are in favor of this candidate?
0.632
0.189
0.213
0.508
Problem 2
Given the following discrete probability distribution, calculate the expected value of the random variable X. Round your answer to 2 significant places after the decimal.
x P(x)
-2 0.15
3 0.43
5 0.16
6 0.26
Problem 3
In a shipment of 150 transistors, 20 are defective. A quality control manager randomly selects 10 transistors. What is the probability that 2 among the selected transistors are defective?
0.22
0.10
0.40
0.26
none of the above
Problem 4
The lifetime of a brand of light bulbs is exponentially distributed with an average of 1800 hours. What is the probability that a randomly selected light bulb will last between 2000 and 2200 hours. Round your answer to 3 significant places after the decimal.
Problem 5
A typist makes an average of 4 typo errors per page that she types. If the number of errors per each typed page can be modeled according to the Poisson distribution, what is the probability that she will make more than 3 typo errors in the next page? Express your answer in decimals and round to two significant places after the decimal. For example 0.1678 should be entered as 0.17.
Problem 6
The amount of break fluid in a certain brand of 12 ounce containers is normally distributed with a mean of 12.1 ounce and a standard deviation of 0.35 ounce. If a random sample of 16 such containers is selected, what is the probability that the average content of the sample is more than the advertised 12 ounces?
0.67
0.81
0.87
0.96
Problem 7
The following is a probability distribution for a discrete random variable. What is the missing value in the probability column?
x P(x)
1 0.33
2
4 0.08
7 0.59
0.16
0.18
0.08
0
Problem 8
The lifetime of a brand of light bulbs is exponentially distributed with an average of 2500 hours. What is the probability that a randomly selected light bulb will last longer than 2000 hours. Round your answer to 2 significant places after the decimal.
Problem 9
Given the following discrete probability distribution, calculate the variance of the random variable X. Round your answer to 2 significant places after the decimal.
x P(x)
-2 0.15
3 0.43
5 0.16
6 0.26
Problem 10
The distribution of scores in a exam has a normal distribution with a mean of 65 and a standard deviation of 8. What is the probability that a randomly selected score was at most 56. Enter your answer using decimal notation (and not percentages), and round your result to 2 significant places after the decimal (for example the probability of 0.1877 should be entered as 0.19)
Problem 11
The distribution of the amount of a certain brand of soda in 16 OZ bottles is approximately normal with a mean of 16.05 OZ and a standard deviation of 0.10 OZ. The percentage of the soda bottles that contain more than the 16 OZ advertised is: _______%.
Write your answer in percent, and round to the nearest whole percent. Do not include a percent sign (%) in your answer. (For example, 0.1678 should be entered as 17)
Problem 12
In a shipment of 80 transistors, 12 are defective. A quality control manager randomly selects 5 transistors. What is the probability that there is more than one defective transistor in the sample?
0.16
0.43
0.57
0.84
none of the above
Problem 13
The popularity rate of a political candidate is 57%. If 20 citizens are randomly selected, what is the probability that exactly 11 in the sample are in favor of this candidate?
0.213
0.507
0.174
0.038.