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5.2 Mean and Standard Deviation of Discrete RV

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Last updated 22 days ago
11 questions
Use the following situation to answer questions 5-8:
Ana is a dedicated Skee Ball player who always rolls for the 50-point slot. The probability distribution of Ana's score X on a randomly selected roll of the ball is shown here.
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Use the following situation to answer questions 1-4:
El Dorado Community College considers a student to be full-time if he or she is taking between 12 and 18 hours. The tuition charge for a full time student is $50 per hour. Suppose we choose a full-time student at random. The probability distribution for the random variable T = tuition charge for the chosen student is shown here.
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Question 1
1.

Make a histogram of the probability distribution.

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Question 5
5.

Calculate the mean of X.

Question 6
6.
Interpret the mean of X.

If we pick many, many of Ana's randomly selected _______, the average _______ will be about _______(mean) _______(units).
Question 7
7.
The standard deviation is 12.6. Interpret the standard deviation of X. Round the mean and standard deviation to one decimal place.

Ana's _______ typically varies by about _______(standard deviation) _______(units) from the mean of _______(mean) _______(units).
Use the following situation to answer questions 9-11:
Casey decides to apply for a job selling mobile phones. She receives a base salary of $200 per month and $15 for every phone sold. The following table shows the probability of a particular number of mobile phones, x, being sold per month.

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Question 8
8.
Calculate the average number of cell phones Casey can expect to sell. _______

If Casey sells this many cell phones, how much would she make? _______

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Question 9
9.
Interpret the mean of X.

If we pick many, many of Casey's randomly selected work months, the average number of _______ sold will be about _______(mean) _______(units).
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The random variable X is the number of houses sold by Christine in a single month at the Oppenheim Group. Its probability distribution is as follows.


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Question 11
11.

What is the average number of houses sold Christine in a single month at the Oppenheim Group?

Question 2
2.

Describe the shape of the histogram of the variable T.

Question 3
3.

Calculate the mean of T.

Question 4
4.

Calculate the standard deviation of T.

Question 10
10.
The standard deviation is 53.86. Interpret the standard deviation of X. Round the mean and standard deviation to two decimal places.

The number of _______ sold typically varies by about _______(standard deviation) _______(units) from the mean of _______(mean) _______(units).