Displaying Quantitative Data with graphs

Let’s grade our homework Remember, I will give you points for completion, not accuracy

Correct Answers 1. Categorical: type of wood, type of water repellant, & paint color Quantitative: paint thickness, weathering time 2. Categorical: gender, race, smoker status Quantitative: age, systolic blood pressure, level of calcium 3. (a) AP Statistics students who completed the survey (b) Categorical: gender, handedness, music Quantitative: height (inches), HW time (minutes), value of pocket change (cents) (c) This individual is female, right-handed, 58 inches tall, spends 60 minutes on homework, prefers alternative music, and had 76 cents in her pocket

Correct Answers 4. (a) Roller coasters opened in 2009 (b) Categorical: Roller Coaster Name, type, & design Quantitative: height (feet), speed (mph), duration (seconds) (c) The Prowler is a wood, sit-down type coaster, is feet in height, goes 51.2 mph, and the duration of its ride is 150 seconds 5. Answers vary. Some examples of categorical: region, type of institution, school colors Some examples of quantitative: graduation rate (% of students), number of students (in students), number of professors (in professors)

Correct Answers 6. Answers vary. some examples of categorical: reality shows (yes or no), documentaries (yes or no) Quantitative: time spent watching tv (minutes), chennels watched (in number of channels) 7. B 8. C 11. (a) (b) Anything logical— Perhaps induced labor and C-section births are scheduled for weekdays

Correct Answers 13. Will vary. Roughly 64% Mexican, roughly 9% Puerto Rican 14. Will vary. Roughly 20% Business, roughly 12% social science 15. (a) The percentages listed are indicating the percentage of that age group, not the percentage of people who bought music (b)

Correct Answers 17. (a) pictures should be proportional to the number of students they represent (b) 19. (a) 133 people; 36 buyers (b) 36.84% said ‘higher,’ 24.06% said ‘the same,’ and 39.1% said ‘lower.’ 60.9% said that they were the same or higher 20. (a) 5375 students total % smoke (b) neither parent smokes: 25.23%. One parent smokes: 41.66%. Both parents smoke: 33.12%

Correct Answers 21. Those that buy recycled products are much more likely to consider them to be of higher quality, though a large minority (25%) still consider them inferior 23. Americans are much more likely to choose white or red than Europeans, while Europeans are more likely than Americans to choose black, silver, or gray HigherThe sameLower Buyers55.56%19.44%25% Non-buyers29.9%25.77%44.33%

Correct Answers 25. State: Among visitors to Yellowstone, what is the relationship between environmental organization membership and snowmobile use? Plan: We will compare the conditional distributions for snowmobile use for those who belong to environmental organization and for those who do not Do: Conclude: Those who are in an environmental group are much less likely to rent or own snowmobiles, and much more likely to have never used them Never UsedRenterOwner Member69.5%25.2%5.2% Non-member36.4%40.7%22.9%

Correct Answers 26. State: Do the data support the idea that people who get angry easily tend to be more likely to have heart disease? Plan: We will compare the conditional distributions of heart disease for different anger levels Do: Conclude: While the occurrence of CHD is low for all levels of anger, there is an increase in CHD as anger increases Low AngerMod. AngerHigh Anger CHD1.7%2.3%4.3% No CHD98.3%97.7%95.7%

Correct Answers 27. D 28. B 29. D 30. D 31. E 32. C

Now on to New Stuff

How to describe: 1. Shape: where is the peak? Is one tail longer than the other (skewed)? 2. Center: where is the center point (or the median)? 3. Spread: minimum and maximum 4. Outliers: Are there any outliers? SOCS

Stemplots I do not like them I do not find them helpful But you’re expected to know what they are Does anyone know what a stemplot is?

Stemplots Let’s say that the class gets the following test grades: 42, 67, 73, 78, 82, 84, 86, 91, 91, 94, 99 The Stemplot would look like

Stemplots You can also use a stemplot to compare two different datasets

Histograms The most common graph of a quantitative variable Also, in my opinion, the most useful Similar to a dotplot, but for larger datasets

Histograms Notice that this is telling us the same information as a dotplot Just larger counts Looks a bit cleaner to some people

Histograms However, there are problems with histograms Our eyes respond to the area of the bars Can be confused with a bar graph Bar graph is for categorical variables Other problems (see pages 39-41)

Your HW is: Chapter 1 (Page 42): 37-47, 53-60, and 68-74