Chapter 101 Graphs, Good and Bad

Chapter 102 Thought Question 1 What is confusing or misleading about the following graph?

Chapter 103 Distribution u Tells what values a variable takes and how often it takes these values u Can be a table, graph, or function

Chapter 104 Variables u Categorical –Places an individual into one of several groups or categories –Display distribution with a bar graph or a pie chart u Quantitative (Numerical) –Takes numerical values for which arithmetic operations such as adding and averaging make sense

Chapter 105 Case Study (from Ch.1) The Effect of Hypnosis on the Immune System u Easy or difficult to achieve hypnotic trance u Group assignment u Pre-study white blood cell count u Post-study white blood cell count categorical quantitative

Chapter 106 Case Study (from Ch.1) Weight Gain Spells Heart Risk for Women u Age (in 1976) u Weight in 1976 u Weight at age 18 u Incidence of coronary heart disease u Other: smoking, family history, menopausal status, post-menopausal hormone use. quantitative categorical

Chapter 107 Class Make-up on First Day (Summer 2002) YearCountPercent Freshman1841.9% Sophomore1023.3% Junior614.0% Senior920.9% Total % Data Table

Chapter 108 Pie Chart Class Make-up on First Day (Summer 2002)

Chapter 109 Class Make-up on First Day (Summer 2002) Bar Graph

Chapter 1010 Line Graphs u A line graph shows behavior over time. u Time is always on the horizontal axis. u Look for an overall pattern (trend). u Look for patterns that repeat at known regular intervals (seasonal variations). u Look for any striking deviations that might indicate unusual occurrences.

Chapter 1011 Class Make-up on First Day (Fall Semesters: )

Chapter 1012 Beware of Pictograms Source: State of the York Watershed 2000, The York Watershed Council, Virginia

Chapter 1013 Another Misleading Graph

Chapter 1014 Making Good Graphs u Title your graph. u Make sure labels and legends describe variables and their measurement units. Be careful with the scales used. u Make the data stand out. Avoid distracting grids, artwork, etc. u Pay attention to what the eye sees. Avoid pictograms and tacky effects.

Chapter 1015 Key Concepts u Categorical and Quantitative Variables u Distributions u Pie Charts u Bar Graphs u Line Graphs u Techniques for Making Good Graphs