Exam 4: A: Numerical Descriptive Techniques

In a negatively skewed distribution,the mean is smaller than the median and the median is smaller than the mode.

The difference between the largest and smallest observations in an ordered data set is called the range.

Which of the following statements about the mean is not always correct?

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

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} Construct a relative frequency histogram for the data,using five class intervals and the value 130 as the lower limit of the first class.

Chebysheff's Theorem applies only to data sets that have a bell shaped distribution.

The median of an ordered data set with 30 items would be the average of the 15^th and the 16^th observations.

Test Scores Suppose that an analysis of a set of test scores reveals that: Q₁ = 45,Q₂ = 85,Q₃ = 105. -{Test Scores Narrative} What can you say about the relative position of each of the observations 34,84,and 104,within this data set?

Ages of Volunteers The following data represent the ages in years of a sample of 25 volunteers from a charitable organization: 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 Volunteers Narrative} Compute the coefficient of variation and express the number in the appropriate unit.

Which of the following statistics is a measure of central location?

A statistic that interprets the standard deviation relative to the size of the numbers in the data set is called the ____________________ of ____________________.

There are three statistics used to measure variability in a data set;the range,the ____________________,and the ____________________.

According to the Empirical Rule,if the data form a bell shaped normal distribution approximately ____________________ percent of the observations will be contained within 3 standard deviations around the mean.

The mean is affected by extreme values but the median is not.

Which of the following statements is true?

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.

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} Construct a stem and leaf display for the number of workers.

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.

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 mean is a measure of variability.