AP Statistics Chapter 2. The Five Ws *Who -are the cases *What -are the variables ( gives information about each of the cases) *Why -helps us to decide.
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AP Statistics Chapter 2
The Five Ws *Who -are the cases *What -are the variables ( gives information about each of the cases) *Why -helps us to decide which way to treat the variable When - Where - *hoW- can make the difference between insight and nonsense
Classification of Variables Categorical variables- indentify a category for each case. ( usually think about counts of cases that fall into each category) or a variable that names categories can by with numerals or words Quantitative variables- record measurements or amounts of something. Must have units or a variable in which the numbers act as numerical values
Vocabulary Context- The context ideally tells Who was measured, What was measured, How the data were collected, and the when and the why the study was performed. Data -Systematically recorded information, whether number or labels, together with its context.
Vocabulary Continued Data Table- An arrangement of data in which each row represents a case and each column represents a variable. Case - is an individual about whom or which we have data. Population - all cases we wish we knew about Sample -the cases we actually examine in seeking to understand the much larger population
Vocabulary Continued Variable - hold the information about the same characteristic for many cases. Units- a quantity or amount adopted as a standard measurement, such as dollars, hours or grams
Our data collection What are some of the things you learned about the class by inspecting our data?
Example 2 Consider the numbers 17, 21, 44, 76. Are those data?
Example 2 cont 17, 21, 44, 76 Context is critical- they could be test score, ages in a golf foursome, or uniform numbers of the starting backfield on the football team. Our reaction changes
Example 3 What are the five Ws of the following data A consumer repots article on energy bars gave the name brand, flavor, price, number of calories, and grams of protein and fat. Who: What: When: Where: How : Why:
Example 3 cont Categorical Variables: Quantitative Variables:
Example 4 A report on the Boston Marathon listed the runners gender, country, age, and time. Who: What: When: Where: How : Why:
Example 5 Cont Categorical Variables: Quantitative Variables: