Intro to Statistics and Stem Plots

12.1 Intro to Statistics

12.2 Stem Plots

Finite Math

EQ: Tuesday, March 26, 2024

• Why do we study Statistics?

• How do I read a Stem Plot?

​How do you know if the soup is too spicy?

Population vs. Sample

Sample

Population

Population vs. Sample

Sample

Population

Spiciness
=
info desired

​Statistics

to INFER a conclusion about the population from a sample

​Statistics

to INFER a conclusion about the population from a sample


the information desired can be
quantitative - can do math with
categorical - types of groups

​Frequency

​categories

​scale

​Categorical

​Quantitative

Averages for Adults 20 years and over


Men Height - 69.0 in
Weight - 199.8 lbs
Waist - 40.5 in

Women Height - 63.5 in
Weight - 170.8 lbs
Waist - 38.7 in

​Samples

What makes a good sample?

​What is one value that could represent your academics in high school?

​What is one value that could represent your academics in high school?



What is one value that could represent the age of students in this class?

Measure of Central Tendency
Measure of Center

A value that can be used to describe a population.

Measure of Central Tendency

Mean

Average = (sum) ÷ how many

Median

When listing in order, the middle number

Mode

The value(s) that show up the most.

Midrange

Average of Max and Min = (max + min) ÷ 2

Measure of Central Tendency

Mean

Average = (sum) ÷ how many

Median

When listing in order, the middle number

Mode

The value(s) that show up the most.

Midrange

Average of Max and Min = (max + min) ÷ 2

​− best for homogeneous data (no outliers): 23, 24, 25, 26, 26

Measure of Central Tendency

Mean

Average = (sum) ÷ how many

Median

When listing in order, the middle number

Mode

The value(s) that show up the most.

Midrange

Average of Max and Min = (max + min) ÷ 2

​− best for homogeneous data (no outliers): 23, 24, 25, 26, 26

​− best for data with outlier(s): 23, 24, 25, 26, 481

Measure of Central Tendency

Mean

Average = (sum) ÷ how many

Median

When listing in order, the middle number

Mode

The value(s) that show up the most.

Midrange

Average of Max and Min = (max + min) ÷ 2

​− best for homogeneous data (no outliers): 23, 24, 25, 26, 26

​− best for data with outlier(s): 23, 24, 25, 26, 481

​− best for consistent data: 23, 24, 23, 22, 29, 23

Measure of Central Tendency

Mean

Average = (sum) ÷ how many

Median

When listing in order, the middle number

Mode

The value(s) that show up the most.

Midrange

Average of Max and Min = (max + min) ÷ 2

​− best for homogeneous data (no outliers): 23, 24, 25, 26, 26

​− best for data with outlier(s): 23, 24, 25, 26, 481

​− best for consistent data: 23, 24, 23, 22, 29, 23

​− best for symmetrical data: 22, 23, 26, 29, 30

Mean, Median or Mode

Which measure would these students to describe their test scores?

Ruben: 92, 94, 92, 89, 98, 95

Teresa: 80, 80, 81, 0, 0, 82

Shana: 95, 25, 41, 23, 95, 38

Outliers
A value that does not appear to be part of the data set.




17, 18, 17, 18, 18, 17, 61, 17, 18, 17, 16

Multiple Choice

How many data values are in this set?

• 15

• 5

• 11

• 135000

Stem and Leaf Plot

​Start with the KEY

​10K K

Stem and Leaf Plot

​Start with the KEY

​10K K

​110,000 + 8,000 = 118,000

Stem and Leaf Plot

​Start with the KEY

​10K K

​110,000 + 8,000 = 118,000

​124000, 125000

Stem and Leaf Plot

​Start with the KEY

​10K K

​110,000 + 8,000 = 118,000

​124000, 125000

​135000, 137000, 138000, 139000, 139000

Stem and Leaf Plot

​Start with the KEY

​10K K

​110,000 + 8,000 = 118,000

​124000, 125000

​135000, 137000, 138000, 139000, 139000

​144000, 147000

Stem and Leaf Plot

​Start with the KEY

​10K K

​110,000 + 8,000 = 118,000

​124000, 125000

​135000, 137000, 138000, 139000, 139000

​144000, 147000

​158000

Make a Stem and Leaf Plot

44, 08, 13, 13, 15, 16, 16, 17, 21, 21, 15

Multiple Select

Find the mode of the data set.

• 515,000

• 519,000

• 206,000

• 510,000

Multiple Choice

Find the median of the data set.

• 515,000

• 519,000

• 206,000

• 527,000

Multiple Choice

Find the midrange of the data set.

• 515,000

• 520,500

• 531,500

• 527,000

Multiple Choice

Find the mean of the data set.

• 8

• 12.9

• 8.4

• 31

Fill in the Blanks

Find the mean of the data set.

Fill in the Blanks

Find the mean of the data set.

Rounded to a whole degree.

Fill in the Blanks

Find the median of the data set.

Multiple Choice

Find the median of the data set.

• 9

• 10

• 11

• 12

Math Response

Find the mode of the data set.

Type answer here

Correct Answer: 10000

Deg^°

Rad

Math Response

Find the mode of the data set.

Type answer here

Correct Answer: 10000

Deg^°

Rad

Multiple Select

Find the mode of the data set.

• 292,000

• 299,000

• 323,000

• 308,000

Multiple Choice

Which stem and leaf plot represents the data set?