Exam 4: Numerical Descriptive Techniques

The range, variance, standard deviation, and coefficient of variation are to be used only on ____________________ data.

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

Percentiles can be converted into quintiles and deciles, where quintiles divide the data into fifths, and deciles divide the data into tenths.

The variance is a measure of the linear relationship between two variables.

The ____________________ measures the margin of relative change in the dependent variable.

Which of the following statements is true?

The coefficient of correlation r is a number that indicates the direction and the strength of the linear relationship between the dependent variable y and the independent variable x.

The precision provided by the numerical techniques (mean, median, and standard deviation) provides more useful information than graphical techniques (histograms and box plots) alone.

Any points that lie outside the whiskers on a box plot are called ____________________.

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. -{Weights of Police Officers Narrative} a. Construct a box plot for the weights. b. Are there any extreme values? c. What does the box plot tell you about the distribution of the data?

Ages of Senior Citizens A sociologist recently conducted a survey of citizens 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 22 uninsured senior citizens were as follows: 65, 66, 67, 68, 69, 70, 71, 73, 74, 75, 76, 77, 78, 79, 80, 81, 86, 87, 91, 92, 94, and 97. -{Ages of Senior Citizens Narrative} Calculate the median age of the uninsured senior citizens.

Salaries of Office Workers The following data represent the salaries (in thousands of dollars) of a sample of 13 office workers 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. -{Salaries of Office Workers Narrative} Compute the range.

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

The method used to find the best fitting line through the observations is called the ____________________ method.

A perfect straight line sloping upward would produce a correlation coefficient value of 1.0.

The price-earnings ratios of a sample of stocks have a mean value of 13.5 and a standard deviation of 2.If the ratios have a bell shaped distribution, what can we say about the proportion of ratios that fall between a. 11.5 and 15.5? b. 9.5 and 17.5? c. 7.5 and 19.5?

If two data sets have the same range, the distances from the smallest to largest observations in both sets will be the same.

The value of the standard deviation may be either positive or negative, while the value of the variance will always be positive.

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. -{Yearly Donations Narrative} Compute the upper quartile.

The ____________________ is the square root of the ____________________.