Exam 4: Graphical Descriptive Techniques Numerical Data

Graphical excellence is displayed when a graph has a proper scale, the axis are marked correctly are the graph chosen appropriately tells the truth about the data.

Time-series data may be graphically depicted on a line chart or a bar chart.

Which of the following statements is false?

Construct a frequency distribution and relative frequency distribution for the test grades for a university business statistics class, data given in the following table. Use seven class intervals. 63 74 42 65 51 54 36 56 68 57 62 64 76 67 79 61 81 77 59 38 84 68 71 94 71 86 69 75 91 55 48 82 83 54 79 62 68 58 41 47

When income increases, expenditure on imports tend to increase. Which of the following best describes this relationship?

Which of the following graphical display is can be used to describe relationship between two numerical (quantitative) variables?

A frequency distribution is a listing of the individual observations arranged in ascending or descending order.

The ages of 25 salespersons in an organisation are given below. 47 21 37 53 28 40 30 32 34 26 34 24 24 35 45 38 35 28 43 45 30 45 31 41 56 Construct an ogive for the data, and estimate the proportion of salespersons that are: a. less than 30 years of age. b. more than 40 years of age. c. between 40 and 50 years of age.

The following table shows the annual incomes (in thousands of dollars) and weekly rent payments (dollars) of a sample of 10 individuals in country Victoria: Income 45 51 40 44 48 35 51 55 49 47 Rent 230 280 190 220 270 200 300 310 260 250 a. Draw a scatter diagram for these data with rent payment on the vertical axis. b. Describe the relationship between rent payment and income.

The frequency distribution of the number of years of service for 100 employees is shown below. Years Frequency 0 up to 5 12 5 up to 10 16 10 up to 15 42 15 up to 20 20 20 up to 25 10 Total 100 a. Estimate the proportion of employees who have fewer than 10 years of service. b. Estimate the proportion of employees who have more than 20 years of service. c. Estimate the proportion of employees who have between 10 and 20 years of service.

A relative frequency distribution describes the proportion of data values that fall within each category.

Construct a stem-and-leaf display of the test grades for a university business statistics class, given below. 63 74 42 65 51 54 36 56 68 57 62 64 76 67 79 61 81 77 59 38 84 68 71 94 71 86 69 75 91 55 48 82 83 54 79 62 68 58 41 47

If we draw a straight line through the points in a scatter diagram and most of the points fall relatively close to the line, we say that there is a linear relationship between the two variables.

Graphical deception is acceptable when the graph displays what the statistician would like the reader to believe, as opposed to the truth about the data.

With a line graph, the horizontal axis is stretched out to get a deceptive steeper slope.

Consider the following cumulative frequency distribution. Class limits Cumulative frequency Up to 10 12 Up to 20 29 Up to 30 57 Up to 40 71 Up to 50 95 Find the frequency for each of the following classes. a. 0 up to 10. b. 10 up to 20. c. 20 up to 30. d. 30 up to 40. e. 40 up to 50.

For each of the following numerical variables, describe if the distribution of data would be symmetrical, positively skewed or negatively skewed. a. Annual incomes of employees in a multinational company. b. Weights of 1kilogram labeled bags of flour, processed by a large manufacturing company. c. Grades of students in an easy test.

A list of share prices of 20 Australian companies at the end of a trading day would be an example of time-series data.

When choosing between a line chart and a bar chart to display a time-series of data, if the main objective is to display the overall general movement, or trend, in the time-series, a line chart is best.

Which of the following best describes the shape of the distribution of incomes of all employees in large company?