1. Statistics and Probability 13.1 Basic Statistics
Essential Question: Why is a knowledge of basic statistics helpful in real-world situations?
Statistics and Probability 13.1 Basic Statistics

2. 13-1: Basic Statistics
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. 13.1 Basic Statistics Types of Data Example 1
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. 13.1 Basic Statistics Data Displays Example 2/Example 3/Example 4
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. 13.1 Basic Statistics Flavor Frequency Relative Frequency Vanilla 6
6/30 = 0.2 = 20%
Chocolate 12
12/30 = 0.4 = 40%
Butter pecan 4
4/30 ≈ 0.13 ≈ 13%
Mint chocolate chip 8
8/30 ≈ 0.27 ≈27%

6. 13.1 Basic Statistics 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˚
Vanilla
20%
Mint Chocolate Chip
27%
Butter Pecan
13%
Chocolate
40%

7. 13.1 Basic Statistics 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

8. 13.1 Basic Statistics

9. 13.1 Basic Statistics 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. 13.1 Basic Statistics Stem Plot Choose leading digit(s) as stems
Arrange stems vertically
Last digit is the leaf
Provide a key

11. 13.1 Basic Statistics 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, 64 3 2 4 5 6
3 4 7 7 8 9 10
3|2 = 32

12. 13.1: Basic Statistics Assignment Page 851 Problems: 1 – 9 (all)
11, 15
19 – 24 (all)