Putting It Together: Sullivan Statistics Survey One

Problem 37E

Putting It Together: Sullivan Statistics Survey One question from the Sullivan Statistics Survey was “How many credit cards do you currently have?” This question was asked of only those individuals who have a credit card. Answer the following questions based on the results of the survey.

(a) Determine the mean number of credit cards based on the raw data.

(b) Determine the standard deviation number of credit cards based on the raw data.

(c) Determine a probability distribution for the random variable, X, the number of credit cards issued to an individual.

(d) Draw a probability histogram for the random variable X. Describe the shape of the distribution.

(e) Determine the mean and standard deviation number of credit cards from the probability distribution found in part (c).

(f) Determine the probability of randomly selecting an individual whose number of credit cards is more than two standard deviations from the mean. Is this result unusual?

(g) Determine the probability of randomly selecting two individuals who are issued exactly two credit cards.[Hint: Are the events independent?] Interpret this result.

                                                              Step-by-step solution

Step 1 of 7 

Choose the data of the variable “How may credit cards do you currently have” from the Sullivan survey.

(a)

To determine the mean number based on the raw data, follow the below instructions of Minitab:

1. Enter the raw data of the variable “Number of cards” in the first column, C1.

2. Select Stat menu and highlight Basic Statistics then choose Display Descriptive

    Statistics…

3. Select the data in the Variables window and then select Statistics and check only Mean

    Option.

4. Then Click OK twice.