Exam 4: Numerical Descriptive Techniques

A basketball player has the following points for seven games: 20, 25, 32, 18, 19, 22, and 30. Compute the following measures of variability. a.Standard deviation b.Coefficient of variation c.Compare the standard deviation and coefficient of variation and use them to discuss the variability in the data.

NARRBEGIN: Ages of Workers Ages of Workers The ages (in years) of three groups of workers are shown below: GROUP A: 17 22 20 18 23 GROUP B: 30 28 35 40 25 GROUP C: 44 39 54 21 52 NARREND -The annual percentage rates of return over the past 10 years for two mutual funds are as shown below. Which fund would you classify as having the higher level of risk? Fund A: 7.1 -7.4 19.7 -3.9 32.4 41.7 23.2 4.0 1.9 29.3 Fund B: 10.8 -4.1 5.1 10.9 26.5 24.0 16.9 9.4 -2.6 10.1

The scale used on a bar chart does not affect the way the bar chart looks.

When two variables x and y are linearly related, it does not necessarily mean that x ____________________ y.

NARRBEGIN: Salaries of Employees Salaries of Employees The following data represent the yearly salaries (in thousands of dollars) of a sample of 13 employees of a firm: 26.5, 23.5, 29.7, 24.8, 21.1, 24.3, 20.4, 22.7, 27.2, 23.7, 24.1, 24.8, and 28.2.NARREND -The mean of a sample of 15 measurements is 35.6 feet. Suppose that the sample is enlarged to 16 measurements, by including one additional measurement having a value of 42 feet. Find the mean of the sample of the 16 measurements.

NARRBEGIN: Credit Hours Credit Hours The College of Business at The State University of California produced 3,400 credit hours during Spring Semester, 2011he number and percentage of credit hours produced by each of the four departments in the College of Business is shown below. Department Percent Count Marketing 35.3 1.200 Management 23.5 800 Finance 23.5 800 Accounting 17.6 600 The following three-dimensional pie chart was constructed from the table above. NARREND -Samantha recorded her amount of exercise time (in minutes) for 100 days. Both of the line charts below were created based on her same data set. Which line chart makes her exercise times look more variable and why?

NARRBEGIN: Hours Worked per Week Hours Worked per Week The following data represent the hours worked per week of a sample of 25 employees from a government department: 31, 43, 56, 23, 49, 42, 33, 61, 44, 28, 48, 38, 44, 35, 40, 64, 52, 42, 47, 39, 53, 27, 36, 35, and 20.NARREND -{Hours Worked per Week Narrative} Compare the mean and median hours for these employees and use them to discuss the shape of the distribution.

NARRBEGIN: Ages of Retirees Ages of Retirees A sociologist recently conducted a survey of retirees over 65 years of age whose net worth is too high to qualify for Medicaid and who have no private health insurance. The ages of 20 uninsured retirees were as follows: 65, 66, 67, 68, 69, 70, 71, 73, 74, 75, 78, 79, 80, 81, 86, 87, 91, 92, 94, and 97.NARREND -{Ages of Retirees Narrative} What does the value of the third quartile tell you?

NARRBEGIN: Strip Mall Rent Strip Mall Rent Monthly rent data in dollars for a sample of 10 stores in a small town in South Dakota are as follows: 220, 216, 220, 205, 210, 240, 195, 235, 204, and 250.NARREND -{Strip Mall Rent Narrative} Compute the sample median.

Generally speaking, if two variables are unrelated (as one increases, the other shows no pattern), the covariance will be:

NARRBEGIN: Yearly Donations Yearly Donations The following data represent the yearly donations (in thousands of dollars) of a sample of 13 benefactors: 26.5, 23.5, 29.7, 24.8, 21.1, 24.3, 20.4, 22.7, 27.2, 23.7, 24.1, 24.8, and 28.2.NARREND -{Yearly Donations Narrative} Compute the upper quartile.

The length of the box in the box plot portrays the:

NARRBEGIN: Hours of Playing Video Ga Hours of Playing Video Games Suppose that the following data provide the hours of playing video games per week for a sample of 15 high school students in Roanoke, Virginia: 5, 11, 25, 19, 18, 20, 27, 13, 8, 10, 15, 19, 18, 9, and 12.NARREND -{Hours of Playing Video Games Narrative} Determine the location and value of the second quartile.

Which of the following is a measure of variability?

NARRBEGIN: Pets Survey Pets Survey A sample of 40 families were asked how many pets they owned. Their responses are summarized in the following table. Number of Pets 0 1 2 3 4 5 Number of Families 3 20 5 4 2 2 NARREND -How do the mean, median and mode compare to each other when the distribution is: a.symmetric? b.negatively skewed? c.positively skewed?

NARRBEGIN: Children Computers The following data represent the number of computers owned by a sample of 10 families from Chicago: 4, 2, 1, 1, 5, 3, 0, 1, 0, and 2.NARREND -{Computers Narrative} Compute the mean number of computers.

The slope b₁ of the least squares line $\tilde { y } = b _ { 0 } + b _ { 1 } x$ represents the:

Is it fair to depict Texas as most tornado prone area of the U.S. by showing it has the highest number of tornados of all states in the U.S.?

NARRBEGIN: Weights of Police Officer Weights of Police Officers The following data represent the weights in pounds of a sample of 25 police officers: 164, 148, 137, 157, 173, 156, 177, 172, 169, 165, 145, 168, 163, 162, 174, 152, 156, 168, 154, 151, 174, 146, 134, 140, and 171.NARREND -{Weights of Police Officers Narrative} Determine the location and value of the second quartile of the weights.

The sample mean is denoted by ____________________ and the population mean is denoted by ____________________.