Unit #1 Review Flashcards

1
Q

What is standard deviation

A

Average distance to the mean

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2
Q

What is the empirical rule

A

Mean, 68, 95, 99.7

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3
Q

What is variance

A

Average squared distance to the mean

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4
Q

What is a z score

A

The number of standard deviations away from the mean

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5
Q

What measures of center do we have

A

Mean, Median, Mode

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6
Q

What measures of spread do we have

A

Standard deviation, variance, range, IQR

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7
Q

what center and spread for unimodal/symmetric data

A

Mean and standard deviation

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8
Q

What center and spread for skewed data or outliers

A

Median and IQR

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9
Q

How do you describe distributions (Histograms)

A

Shape, center, spread, strange

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10
Q

How do you describe the shape of a histogram

A

Modes and symmetry

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11
Q

What is visual display for quantitative data

A

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

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12
Q

What is visual display for categorical data

A

Segmented bar, pie, bar, mosaic

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13
Q

What is the IQR

A

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

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14
Q

What are the outliers

A

1.5 IQR below Q1 and 1.5 IQR above Q3

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15
Q

What percent of the data is contained in the IQR

A

50%

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16
Q

Norm CDF inputs

A

HI, LO mu, sigma = percent

17
Q

Inv Norm inputs

A

Percentile, mu, sigma = value

18
Q

What is bivariate data

A

Two variables, when you measure two variables from each subject

19
Q

How can you think about independent and association

A

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

20
Q

Example of independent

A

Categorical: Gender and pizza preference
Quantitative: Height and IQ

21
Q

Example of associated

A

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

22
Q

With categorical bivariate, what would independence look like

A

Similar/same percent distribution across

23
Q

With quantitative bivariate, what would independence look like

A

The regression slope would be zero

24
Q

How do you describe scatterplots

A

Direction, form, strength, strange

25
Q

What does R value tell you

A

Direction and strength of a model

26
Q

What does R^2 tell you

A

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

27
Q

What is Sy/Sx

A

This is the slope of the regression line

28
Q

What point is on every regression line

A

X-bar, Y-bar

29
Q

Slope in context

A

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

30
Q

Y intercept in context

A

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

31
Q

What is a residual

A

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

32
Q

What do you want the residual plot to look like

A

Random, no pattern

33
Q

What does standard deviation of residuals tell you

A

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

34
Q

How do you find outliers in regression

A

They don’t follow the FLOW

35
Q

What is the average of all the residuals

A

ZERO

36
Q

What does S tell us in a regression output

A

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

37
Q

Difference between scatter plot and resid plot on calculator

A

L1vL2

L1vRESID