Chapter Eight: Using Statistics to Answer Questions

1. Chapter Eight: Using Statistics to Answer Questions

2. Chapter Eight: Using Statistics to Answer Questions • Statistics

3. Chapter Eight: Using Statistics to Answer Questions • Statistics • Statistics is a branch of mathematics that involves the collection, analysis, and interpretation of data.

4. Chapter Eight: Using Statistics to Answer Questions • Statistics • Statistics is a branch of mathematics that involves the collection, analysis, and interpretation of data. • Two main branches of statistics assist your decisions in different ways.

5. Chapter Eight: Using Statistics to Answer Questions • Statistics • Statistics is a branch of mathematics that involves the collection, analysis, and interpretation of data. • Two main branches of statistics assist your decisions in different ways. • Descriptive Statistics

6. Chapter Eight: Using Statistics to Answer Questions • Statistics • Statistics is a branch of mathematics that involves the collection, analysis, and interpretation of data. • Two main branches of statistics assist your decisions in different ways. • Descriptive Statistics • Descriptive statistics are used to summarize any set of numbers so you can understand and talk about them more intelligibly.

7. Chapter Eight: Using Statistics to Answer Questions • Statistics • Statistics is a branch of mathematics that involves the collection, analysis, and interpretation of data. • Two main branches of statistics assist your decisions in different ways. • Descriptive Statistics • Inferential Statistics

8. Chapter Eight: Using Statistics to Answer Questions • Statistics • Statistics is a branch of mathematics that involves the collection, analysis, and interpretation of data. • Two main branches of statistics assist your decisions in different ways. • Descriptive Statistics • Inferential Statistics • Inferential statistics are used to analyze data after you have conducted an experiment to determine whether your independent variable had a significant effect.

9. Descriptive Statistics • We use descriptive statistics when we want to summarize a set or distribution of numbers in order to communicate their essential characteristics.

10. Descriptive Statistics • We use descriptive statistics when we want to summarize a set or distribution of numbers in order to communicate their essential characteristics. • One of these essential characteristics is a measure of the typical or representative score, called a measure of central tendency.

11. Descriptive Statistics • We use descriptive statistics when we want to summarize a set or distribution of numbers in order to communicate their essential characteristics. • One of these essential characteristics is a measure of the typical or representative score, called a measure of central tendency. • A second essential characteristic that we need to know about a distribution is how much variability or spread exists in the scores.

12. Scales of Measurement • Measurement

13. Scales of Measurement • Measurement • The assignment of symbols to events according to a set of rules.

14. Scales of Measurement • Measurement • The assignment of symbols to events according to a set of rules. • Scale of measurement • A set of measurement rules

15. Scales of Measurement • Nominal Scale

16. Scales of Measurement • Nominal Scale • A scale of measurement in which events are assigned to categories.

17. Scales of Measurement • Nominal Scale • A scale of measurement in which events are assigned to categories. • Ordinal Scale

18. Scales of Measurement • Nominal Scale • Ordinal Scale • A scale of measurement that permits events to be rank ordered.

19. Scales of Measurement • Nominal Scale • Ordinal Scale • Interval Scale

20. Scales of Measurement • Nominal Scale • Ordinal Scale • Interval Scale • A scale of measurement that permits rank ordering of events with the assumption of equal intervals between adjacent events.

21. Scales of Measurement • Nominal Scale • Ordinal Scale • Interval Scale • Ratio Scale

22. Scales of Measurement • Nominal Scale • Ordinal Scale • Interval Scale • Ratio Scale • A scale of measurement that permits rank ordering of events with the assumption of equal intervals between adjacent events and a true zero point.

23. Measures of Central Tendency • Mode

24. Measures of Central Tendency • Mode • The score in a distribution that occurs most often.

25. Measures of Central Tendency • Mode • The score in a distribution that occurs most often. • Median

26. Measures of Central Tendency • Mode • The score in a distribution that occurs most often. • Median • The number that divides a distribution in half.

27. Measures of Central Tendency • Mode • The score in a distribution that occurs most often. • Median • The number that divides a distribution in half. • Mean

28. Measures of Central Tendency • Mode • The score in a distribution that occurs most often. • Median • The number that divides a distribution in half. • Mean • The arithmetic average of a set of numbers. It is found by adding all the scores in a set and then dividing by the number of scores.

29. Graphing Your Results • Pie Chart

30. Graphing Your Results • Pie Chart • Graphical representation of the percentage allocated to each alternative as a slice of a circular pie.

31. Graphing Your Results • Pie Chart • Histogram

32. Graphing Your Results • Pie Chart • Histogram • A graph in which the frequency for each category of a quantitative variable is represented as a vertical column that touches the adjacent column.

33. Graphing Your Results • Pie Chart • Histogram • Bar Graph

34. Graphing Your Results • Pie Chart • Histogram • Bar Graph • A graph in which the frequency for each category of a qualitative variable is represented as a vertical column. The columns of a bar graph do not touch.

35. Graphing Your Results • Pie Chart • Histogram • Bar Graph • Frequency Polygon

36. Graphing Your Results • Pie Chart • Histogram • Bar Graph • Frequency Polygon • A graph that is constructed by placing a dot in the center of each bar of a histogram and then connecting the dots.

37. Graphing Your Results • Pie Chart • Histogram • Bar Graph • Frequency Polygon • Line Graph

38. Graphing Your Results • Pie Chart • Histogram • Bar Graph • Frequency Polygon • Line Graph • A graph that is frequently used to depict the results of an experiment. The vertical or y axis is known as the ordinate and the horizontal or x axis is known as the abscissa.

39. Calculating and Computing Statistics • You can find statistical formulas in Appendix B of your text.

40. Calculating and Computing Statistics • You can find statistical formulas in Appendix B of your text. • All statistical formulas merely require addition, subtraction, multiplication, division, and finding square roots.

41. Calculating and Computing Statistics • You can find statistical formulas in Appendix B of your text. • All statistical formulas merely require addition, subtraction, multiplication, division, and finding square roots. • Your department may have access to some standard statistical packages such as SPSS, SAS, BMD, Minitab, etc.

42. Measure of Variability • Variability

43. Measure of Variability • Variability • Range

44. Measures of Variability • Variability • Range • A measure of variability that is computed by subtracting the smallest score from the largest score.

45. Measures of Variability • Variability • Range • Variance

46. Measures of Variability • Variability • Range • Variance • A single number that represents the total amount of variation in a distribution.

47. Measures of Variability • Variability • Range • Variance • Standard Deviation

48. Measures of Variability • Variability • Range • Variance • Standard Deviation • The standard deviation is the square root of the variance. It has important relations to the normal curve.

49. Measures of Variability • Normal distribution

50. Measures of Variability • Normal distribution • A symmetrical, bell-shaped distribution having half the scores above the mean and half the scores below the mean.