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Essential Question: Why is a knowledge of basic statistics helpful in real-world situations?

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Presentation on theme: "Essential Question: Why is a knowledge of basic statistics helpful in real-world situations?"— Presentation transcript:

1 Essential Question: Why is a knowledge of basic statistics helpful in real-world situations?

2  Population: The set of all people who can be chosen  Sample: The set of people from the population who were actually chosen  Example: Identify the population and the sample  There are three schedule options for classes at a high school: 90- minute classes every other day for a year, 90-minute classes every day for a semester or 45-minute classes every day for a year. Out of 1200 students, 50 students from each grade level are chosen at random and asked their preference. ▪ Population: ▪ Sample: 1200 students 50 students 4 grades = 200 students

3  Types of Data  Qualitative – categorical  Quantitative – numerical ▪ Discrete – incremental ▪ Continuous – no minimum difference  Example 1  The height of each player on a basketball team ▪  The style of shoes worn by each student in a class ▪  The number of people in each household in the US ▪ Quantitative - continuous Qualitative Quantitative - discrete

4  Data Displays  Frequency – number of times a value appears  Relative frequency – frequency / total number of items  Example 2/Example 3/Example 4  30 people were asked their favorite flavor of ice cream: 6 vanilla, 12 chocolate, 4 butter pecan, 8 mint chocolate chip.  Display as a frequency table, bar graph, and pie chart

5 FlavorFrequencyRelative Frequency Vanilla66/30 = 0.2 = 20% Chocolate1212/30 = 0.4 = 40% Butter pecan44/30 ≈ 0.13 ≈ 13% Mint chocolate chip88/30 ≈ 0.27 ≈27%

6  Pie Chart  Each relative frequency takes a portion of 360˚ ▪ Vanilla: 0.2 ∙ 360˚ = 72˚ ▪ Chocolate: 0.4 ∙ 360˚ = 144˚ ▪ Butter pecan : 0.13 ∙ 360˚ ≈ 47˚ ▪ Mint chocolate chip: 0.27 ∙ 360˚ ≈ 97˚ Chocolate 40% Vanilla 20% Butter Pecan 13% Mint Chocolate Chip 27%

7  Displaying Quantitative Data  Curve types ▪ Uniform – all values have approximately same frequency ▪ Symmetric – right and left sides are mirror images ▪ Skewed right – right side lower than the left side ▪ Skewed left – left side lower than the right side  Skewed means “screwed”  Outlier – data far removed from the rest. ▪ Usually the culprit in skewed data

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9  Example 5 - The shape of data  Choose the best determination of data (uniform, symmetric, skewed right, skewed left) ▪ The last digit of each number in the phone book ▪ ▪ The salaries of the employees of a corporation ▪ ▪ The age of retirement for all people in the US ▪ ▪ The height of all adult women in the US ▪ Uniform Skewed right Skewed left Symmetric

10  Stem Plot  Choose leading digit(s) as stems  Arrange stems vertically  Last digit is the leaf  Provide a key

11  31 test scores on an exam  32, 67, 89, 90, 87, 72, 75, 88, 95, 83, 97, 72, 85, 93, 79, 63, 70, 87, 74, 86, 98, 100, 97, 85, 77, 88, 92, 94, 81, 76, |2 = 32

12  Assignment  Page 851  Problems: ▪ 1 – 9 (all) ▪ 11, 15 ▪ 19 – 24 (all)


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