Describing Distributions

Question 3

If the graph of your data is skewed, what center and measure of spread should you use?

Answer 3

Center: Median

Measure of Spread: IQR

Question 4

How to interpret R² (Coefficient of Determination)

Answer 4

Coefficient of Determination : (R² as a percent) of the change in (Y) can be explained by the change in (X)

Example Problem:

Given that R² is .99, Y = height, and X= age, describe what it means in the context of the situation.

-99% of the change in height (Y) can be explained by the change in age (X)

Question 4

Answer 4

Pie Chart

Question 5

Answer 5

Stem Plot

Question 5

What type of graph would you make with this information?

Answer 5

Ogive

Question 6

Answer 6

Dot Plot

Question 7

What is the center?

Answer 7

The middle of the distribution, first located by finding the highest peak. It is measured by mean, median, or mode.

Question 7

What is IQR?

What is its equation?

When do you find the IQR for spread?

Answer 7

• Inner Quartile Range
• Q3-Q1=IQR
• You use it when the shape of the graph is skewed

Question 7

Answer 7

Histogram

Question 7

Answer 7

Bar Graph

Question 9

What is mean; its equation?

Answer 9

The average; the sum of the data divided by the number of numbers.

Question 10

What is a median?

Answer 10

The middle # when the numbers are in numerical order.

Question 11

What is the mode and when is it used to describe the center of a graph?

Answer 11

• The number that occurs the most
• When the graph’s shape is bimodal

Question 11

What is a Population?

Answer 11

Used to measure all possible outcomes in a particular study.

Question 11

How do you find the outliers in a set of data?

Answer 11

Low outliers: Q1-(1.5*IQR)

High outliers: Q3+(1.5*IQR)

Question 12

True or False. When looking at the United States, the city of New York is a population.

Answer 12

False

Question 13

Practice Problem A study found correlation r=0.61 between the sex of a worker and his or her income. You conclude that

A. Women earn more than men on the average.

B. Women earn less than men on average.

C. An arithmetic mistake was made; this is not a possible value of r.

D. This is nonsense because r makes no sense here.

Answer 13

D. This is nonsense because r makes no sense here.

Question 13

Practice Problem

Which of the folowing would not be a correct interpretation of a correlation of r=-.30?

A. The variances are inversely related.

B. The coefficient of determination is 0.09.

C. 30% of the varitaion between the variables is linear.

D. There exists a weak relationship between the variables.

E. All of the above statements are correct.

Answer 13

C. 30% of the varitaion between the variables is linear.

Question 13

What is the value of correlation for operating cost per hour and number of passenger seats in the plane? Interpret the correlation.

Answer 13

r=0.75

There is a strong positive linear relationship between the operating cost per hour and the number of passenger seats on the plane.

Question 14

Practice Problem A copy machine dealer has data on the number x of copy machines at each of 89 customer locations and the number of y service calls in a month at each location. It was given that r=0.86. What percent of the variation in number of service calls is explained by the linear relation between number of service calls and number of machines?

A. 86%

B. 93%

C. 74%

D. None of these

E. Can’t tell from the information given

Answer 14

C. 74% The question is asking for r² and since r=0.86, you would square 0.86 and get 0.74.

Question 15

What is a qualitative variable?

Answer 15

A variable that describes non numerical values.

Question 16

What are the two types of qualitative graphs covered in class?

Answer 16

Pie Chart

Bar Graph

Question 17

What is a Quantitative variable?

Answer 17

A numerical variable that represents a measurable quantity.

Question 18

What are the four types of quantitative graphs covered in class?

Answer 18

Stem Plot Histogram Dot Plot Ogive

Question 20

which of the following is Quantitative? a. age b. time c. gender d. number of girls in a class e. number of people in a class

Answer 20

a and e

Question 22

What is range? What is its equation? When do you find range?

Answer 22

* The maximum value minus the minimum value in the data set * Max- Min * You find the range for boxplots and its five-number summary

Question 23

What is the range for correlation coefficient?

Answer 23

-1 to 1

Question 25

How do you find the residual?

Answer 25

y-ŷ

Question 26

What is a Sample?

Answer 26

A portion of a population

Question 27

True or False. A class in a school is a sample.

Answer 27

True

Question 28

What are the possible measures of spread?

Answer 28

Range IQR Variance Standard Deviation

Question 29

What is standard deviation? What is its equation? When do you use standard deviation to find spread?

Answer 29

* The average distance from the mean * You use it when the shape of the graph is symmetric

Question 31

What is a two way table?

Answer 31

IDK, There is a row, column. Add all the number of column and row will give the total amount of the study. 

Question 32

What is variance? What is its equation?

Answer 32

* The square of standard deviation

Question 34

What are the things required to interpret correlation?

Answer 34

Form, strength, and direction

Question 36

What is a Risidual 

Answer 36

The vertical distance from a expected point to the regression line.

Question 37

What is the equation to find the slope (b)?

Answer 37

b=r(Sy/Sx)

Question 39

What is the general equation for a least square regression line

Answer 39

ŷ=a+bx

Question 40

What are the symbols for Correla²tion and Coefficient of Determination?

Answer 40

R = Correlation R² = Coefficient of Determination

Question 41

Which type of quantitative graph organizes your one variable data chronologically so that, for example, all of the data in the 20-29 region would be grouped together with a 2 on one side of a line and a list of the changing ones place (2 2 3 4 4 7)?

Answer 41

Stem Plot

Question 42

Which type of 1-variable quantitative graph does not necessarily need a y-axis label and stacks a dot over it's x value for each count?

Answer 42

Dot Plot

Question 43

Which quantitative graph divides its data into Bin and Counts?

Answer 43

Histogram

Question 44

What quantitative graph divides its x-values into groups and then adds the previous y-values quantity to its own?

Answer 44

Ogive