This document provides an overview of key concepts in statistics including: - Descriptive statistics such as frequency distributions which organize and summarize data - Inferential statistics which make estimates or predictions about populations based on samples - Types of variables including quantitative, qualitative, discrete and continuous - Levels of measurement including nominal, ordinal, interval and ratio - Common measures of central tendency (mean, median, mode) and dispersion (range, standard deviation)

1. What is Statistics

6. Population versus Sample A population is a collection of all possible individuals, objects, or measurements of interest. A sample is a portion , or part, of the population of interest

9. Summary of Types of Variables

11. Summary of the Characteristics for Levels of Measurement

12. Describing Data: Frequency Tables, Frequency Distributions, and Graphic Presentation

14. Bar Charts

15. Pie Charts

16. Pie Chart Using Excel

18. Frequency Table

21. EXAMPLE – Creating a Frequency Distribution Table Ms. Kathryn Ball of AutoUSA wants to develop tables, charts, and graphs to show the typical selling price on various dealer lots. The table on the right reports only the price of the 80 vehicles sold last month at Whitner Autoplex.

25. Relative Frequency Distribution To convert a frequency distribution to a relative frequency distribution, each of the class frequencies is divided by the total number of observations.

27. Histogram Histogram for a frequency distribution based on quantitative data is very similar to the bar chart showing the distribution of qualitative data. The classes are marked on the horizontal axis and the class frequencies on the vertical axis. The class frequencies are represented by the heights of the bars.

28. Histogram Using Excel

30. Cumulative Frequency Distribution

31. Cumulative Frequency Distribution

32. Describing Data: Numerical Measures Chapter 3

36. EXAMPLE – Population Mean

38. EXAMPLE – Sample Mean

41. EXAMPLE – Weighted Mean The Carter Construction Company pays its hourly employees $16.50, $19.00, or $25.00 per hour. There are 26 hourly employees, 14 of which are paid at the $16.50 rate, 10 at the $19.00 rate, and 2 at the $25.00 rate. What is the mean hourly rate paid the 26 employees?

46. Example - Mode

47. Mean, Median, Mode Using Excel Table 2–4 in Chapter 2 shows the prices of the 80 vehicles sold last month at Whitner Autoplex in Raytown, Missouri. Determine the mean and the median selling price. The mean and the median selling prices are reported in the following Excel output. There are 80 vehicles in the study. So the calculations with a calculator would be tedious and prone to error.

48. Mean, Median, Mode Using Excel

49. The Relative Positions of the Mean, Median and the Mode

54. Samples of Dispersions

61. The Empirical Rule

62. The Arithmetic Mean of Grouped Data

64. The Arithmetic Mean of Grouped Data - Example

65. Standard Deviation of Grouped Data

67. End of Chapter 3

68. Describing Data: Displaying and Exploring Data Chapter 4

72. Dot Plot – Minitab Example

76. Stem-and-leaf: Another Example

77. Stem-and-leaf: Another Example (Minitab)

83. Percentiles – Example (Minitab)

84. Percentiles – Example (Excel)

85. Boxplot - Example

86. Boxplot Example

90. Commonly Observed Shapes

92. Skewness – An Example Using Pearson’s Coefficient

93. Skewness – A Minitab Example

95. Describing Relationship between Two Variables – Scatter Diagram Examples

97. Describing Relationship between Two Variables – Scatter Diagram Excel Example

100. End of Chapter 4