Exam 4: Numerical Descriptive Techniques

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. ​ ​ -{Hours Worked per Week Narrative} Find the modal hours.

The coefficient of determination is the percentage of variation in the ____________________ variable that is explained by the variation in the ____________________ variable.

In the equation of the least squares line, is the ____________________ and b₁ is the ____________________.

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. ​ ​ -{Ages of Retirees Narrative} What does the value of the first quartile tell you?

According to the Empirical Rule,if the data form a bell shaped normal distribution,approximately ____________________ percent of the observations will be contained within 2 standard deviations around the mean.

Statisticians usually apply graphical techniques as a first step in analyzing data because we first need to know the ____________________ of the distribution.

Another word for the mean of a data set is the ____________________.

The number of hours a college student spent studying during the final exam week was recorded as follows: 6,5,2,8,7,4,and 9.Compute the range for the data,express the number in the appropriate unit.

The range is considered the weakest measure of variability.

Ages of Jockeys ​ The following data represent the ages in years of a sample of 25 jockeys from a local race track: 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. ​ ​ -{Ages of Jockeys Narrative} Find the upper quartile of the ages.

Which of the following measures of variability is not sensitive to extreme values?

A scatter diagram reveals a strong positive linear relationship between oil and gasoline prices.Which of the following numerical techniques will not give us more detailed information about this relationship?

Weights of Teachers ​ The following data represent the weights in pounds of a sample of 25 teachers: 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. ​ ​ -{Weights of Teachers Narrative} Compute the sample variance and sample standard deviation.

Suppose that a firm's sales were $2,500,000 four years ago,and sales have grown annually by 25%, 15%,−5%,and 10% since that time.What was the geometric mean growth rate in sales over the past four years?

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. ​ ​ -{Hours of Playing Video Games Narrative} Determine the location and value of the third quartile.

A data sample has a mean of 107,a median of 122,and a mode of 134.The distribution of the data is positively skewed.

Which measure of central location can be used for both interval and nominal variables?

Weights of Workers ​ The following data represent the number of employees of a sample of 25 companies: 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. ​ ​ -{Weights of Workers Narrative} Find the mean number of workers.

Which of the following are measures of the linear relationship between two variables,but not the strength?

The value for Q₃ can never be smaller than the value for Q₁.