Exam 4: Numerical Descriptive Techniques

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. -{Salaries of Employees Narrative} Compute the median salary.

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 coefficient of variation and express the number in the appropriate unit.

The smaller the spread of scores around the mean:

What statistics and graphs can you use to answer the following questions: Is the distribution unimodal, bimodal, or multimodal? If there is more than one mode, where are the peaks, and where are the valleys?

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} Compute the sample mean hours.

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 median number of workers.

If the standard deviations of x and y are 12.5 and 10.8, respectively, and the covariance is 118.8, then the coefficient of correlation r is 0.88.

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

The 5-number summary consists of the smallest observation, the first quartile, the median, the third quartile, and the largest observation.

The coefficient of correlation and the least squares line both describe the relationship between two interval variables.

If a data set contains an even number of observations, the median is found by taking the ____________________ of these two numbers.

Milk Demand A supermarket has determined that daily demand for milk containers has an approximate bell shaped distribution, with a mean of 55 containers and a standard deviation of six containers. -{Milk Demand Narrative} How often can we expect between 49 and 61 containers to be sold in a day? (Give a percentage.)

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 mean age of the uninsured senior citizens

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.

The length of the box in a box plot portrays the interquartile range.

Assuming a linear relationship between X and Y, if the coefficient of correlation (r) equals -0.75, this means that:

According to the Empirical Rule, if the data form a bell shaped normal distribution approximately ____________________ percent of the observations will be contained within 1 standard deviation around the mean.

If the correlation coefficient r = 1.00, then all the observations must fall exactly on:

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 range and coefficient of variation.

The median of a set of data is more representative than the mean when the mean is larger than most of the observations.