Exam 4: Numerical Descriptive Techniques

NARRBEGIN: Salaries of Office Worker 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.NARREND -{Salaries of Office Workers Narrative} Compute the variance, and standard deviation of the salaries, and express the numbers in the appropriate units.

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

NARRBEGIN: Ages of Jockeys 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.NARREND -{Ages of Jockeys Narrative} Find the lower quartile of the ages.

The variance is more meaningful and easier to interpret compared to the standard deviation.

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} Construct a stem and leaf display for the hours.

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.

NARRBEGIN: Home Care Home Care Data are collected on the number of house calls (x) made in a given week by each of 60 nurses in a certain hospital. The same data set is displayed in each of the three histograms below. NARREND -{Home Care Narrative} How many nurses are there in this hospital?

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 -{Ages of Workers Narrative} Compute and compare the ranges for the three groups.

The advantage that the coefficient of correlation has over the covariance is that the former has set lower and upper limits.

Graphical techniques should not be used to present data if accurate tabular forms for the same data are available.

In a positively skewed distribution:

The Empirical Rule states that the percentage of observations in a data set (providing that the data set is bell shaped) that fall within one standard deviation of their mean is approximately 75%.

Which of the following statements illustrates graphical deception?

The horizontal lines extending to the left and to the right of the box in a box plot are called ____________________.

Generally speaking, if two variables are unrelated, the covariance will be a number close to zero.

The interquartile range will always exceed that of the range.

NARRBEGIN: Ages of Jockeys 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.NARREND -{Ages of Jockeys Narrative} a.Construct a box plot for the ages and identify any extreme values. b.What does the box plot tell you about the distribution of the data?

NARRBEGIN: Ages of Volunteers 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.NARREND -{Ages of Volunteers Narrative} Compute the range of the data, and express the number in the appropriate unit.

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 -A mutual fund you purchased in the years 2011-2014 has the following rates of return shown below: Year 2011 2012 2013 2014 Rate of Return .50 .30 -.10 -.15 Compute the geometric mean.

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 -Suppose your data set contains ages (in years) and you calculate the range, variance, standard deviation, and coefficient of variation for the data. Explain what units each of these measures is in.