Unit #1 Review

Question 1

What is standard deviation

Answer 1

Average distance to the mean

Question 2

What is the empirical rule

Answer 2

Mean, 68, 95, 99.7

Question 3

What is variance

Answer 3

Average squared distance to the mean

Question 4

What is a z score

Answer 4

The number of standard deviations away from the mean

Question 5

What measures of center do we have

Answer 5

Mean, Median, Mode

Question 6

What measures of spread do we have

Answer 6

Standard deviation, variance, range, IQR

Question 7

what center and spread for unimodal/symmetric data

Answer 7

Mean and standard deviation

Question 8

What center and spread for skewed data or outliers

Answer 8

Median and IQR

Question 9

How do you describe distributions (Histograms)

Answer 9

Shape, center, spread, strange

Question 10

How do you describe the shape of a histogram

Answer 10

Modes and symmetry

Question 11

What is visual display for quantitative data

Answer 11

Histogram, box and whisker, dot, time, stem, ogive, normal probability

Question 12

What is visual display for categorical data

Answer 12

Segmented bar, pie, bar, mosaic

Question 13

What is the IQR

Answer 13

Interquartile range, the width of the middle 50% of the data, Q3-Q1

Question 14

What are the outliers

Answer 14

1.5 IQR below Q1 and 1.5 IQR above Q3

Question 15

What percent of the data is contained in the IQR

Answer 15

50%

Question 16

Norm CDF inputs

Answer 16

HI, LO mu, sigma = percent

Question 17

Inv Norm inputs

Answer 17

Percentile, mu, sigma = value

Question 18

What is bivariate data

Answer 18

Two variables, when you measure two variables from each subject

Question 19

How can you think about independent and association

Answer 19

They are opposites, independent means no relationship, associated means there is a relationship

Question 20

Example of independent

Answer 20

Categorical: Gender and pizza preference
Quantitative: Height and IQ

Question 21

Example of associated

Answer 21

Categorical: Gender and video game playing
Quantitative: study time and test score

Question 22

With categorical bivariate, what would independence look like

Answer 22

Similar/same percent distribution across

Question 23

With quantitative bivariate, what would independence look like

Answer 23

The regression slope would be zero

Question 24

How do you describe scatterplots

Answer 24

Direction, form, strength, strange

Question 25

What does R value tell you

Answer 25

Direction and strength of a model

Question 26

What does R^2 tell you

Answer 26

The percent of variability in Y explained by the model with X

Question 27

What is Sy/Sx

Answer 27

This is the slope of the regression line

Question 28

What point is on every regression line

Answer 28

X-bar, Y-bar

Question 29

Slope in context

Answer 29

Model says for each unit of X, there is an increase/decrease of slope units of Y on average

Question 30

Y intercept in context

Answer 30

Where there is no X stuff, the model predicts this much Y stuff

Question 31

What is a residual

Answer 31

Vertical distance from a point to the regression line. It is how far off the true value is from the models prediction

Question 32

What do you want the residual plot to look like

Answer 32

Random, no pattern

Question 33

What does standard deviation of residuals tell you

Answer 33

It is the average, or typical, residual. It is about how far off you expect the predictions to be

Question 34

How do you find outliers in regression

Answer 34

They don't follow the FLOW

Question 35

What is the average of all the residuals

Answer 35

ZERO

Question 36

What does S tell us in a regression output

Answer 36

The typical distance from the model. How far off the model is on average. Expected amount the model will be off by

Question 37

Difference between scatter plot and resid plot on calculator

Answer 37

L1vL2 L1vRESID