Applied Statistics Quiz #1

Front 1

Define: casual variable

Back 1

Independent variable that produces a casual effect on the dependent variable (we cannot prove in this class)

Front 2

Define: confounding variable

Back 2

Extraneous variable that correlates with both the independent and dependent variable (cannot prove in this class)

Front 3

Define: bell curve

Back 3

Symmetric distribution

Front 4

If you are preforming a study and you want to see if it is rare to get 12 bets in a sample of 20 what two formulas would you use?

Back 4

-First, count(Risk_Taker="Yes")
-Second, (number_of_bets_in_a_random_20<12)/(number_of_bets_in_a_random_20)

Front 5

How do you write a conclusion?

Back 5

The probability of a random collection of __ having __ or less/more is (p-value). This is evidence that the experimentally observed correlation between __ and __ is (or is not) caused by random variation alone.

Front 6

What is a summary table and how do you caption it?

Back 6

-Describes experiment
-Date/time, location, circumstance, ect.

Front 7

What is a table and how do you caption it?

Back 7

-Things you're measuring
-Measure count, mean, median

Front 8

What is a graph and how do you caption it?

Back 8

-Shows pattern of data
-Label axes, describe interesting features

Front 9

Where is the independent and dependent variable on a summary table and graph?

Back 9

-Independent on horizontal and bottom of graph
-Dependent on vertical

Front 10

What are the two categories of descriptive statistics?

Back 10

1.Meausre of central tendencies=trying to summarize data by "typical" value
2.Measure of dispersion=indicate through a single number the extent to which a distributions observations vary

Front 11

What are the measures used in central tendencies?

Back 11

Mean, median

Front 12

What are the measures used in dispersion?

Back 12

Standard deviation, IQR

Front 13

Define: mean

Back 13

The mean of a random sample is defined as the sum of the observed values divided by the sum of the sample

Front 14

Define: median

Back 14

Arrange data points in ascending order, the median is the middle observation

Front 15

What's the equation for standard deviation?

Back 15

Square root of (x-xbar)squared/n-1 where n=sample size, x=observed value, and xbar=sample mean

Front 16

What are Q1, Q2, and Q3?

Back 16

-Q1=data point below which 25% of data is
-Q2=data point below which 50% of data is
-Q3=data point below which 75% of data is

Front 17

What is the equation for IQR?

Back 17

Q3-Q1

Front 18

Define: outlier

Back 18

Extreme values not considered common values

Front 19

Define: whiskers

Back 19

Lines extending from the box plot

Front 20

Define: right-skewed distribution

Back 20

Positive skewed distribution with longer right tail

Front 21

Define: left-skewed distribution

Back 21

Negative skewed distribution witha longer left tail

Front 22

Define: symmetric

Back 22

Distribution will have approx. equal tails

Front 23

What are the equations to calculate outliers?

Back 23

-Q1-1.5(IQR) (left outliers)
-Q3+1.5IQR (right outliers)

Front 24

Define: explanatory variable

Back 24

Variable that is manipulated by the experiment, supposed to "explain" the other variable

Front 25

Define: response variable

Back 25

Variable that occurs as a result of the explanatory variable

Front 26

Define: frequency table

Back 26

A table that displays the frequency of different observations, organizes data

Front 27

Define: dichotomos data

Back 27

Data in which observations can only be one of two things

Front 28

Define: categorical data

Back 28

Data in which observations fit in finite categories

Front 29

Define: quantitative data

Back 29

Data in which observations take a numerical value

Front 30

Define: odds ratio

Back 30

-Ratio of the odds of one group and another group
-p(1-p)/q(1-q)

Front 31

Define: p-value (relative frequency)

Back 31

The probability that the results from an experiment are entirely due to chance

Front 32

Define: measure of a sample

Back 32

A single number that summarizes a sample

Front 33

Define: randomized distribution

Back 33

A distribution applied to many random samples of data

Front 34

How do you assess two dichotomous variables?

Back 34

-2x2 frequency table
-Bar graph
-We can sample

Front 35

How do you assess one continuous variable?

Back 35

-5 number summary
-Box plot
-Can't sample

Front 36

How do you assess two continuous variables

Back 36

-5 number summary
-Histogram or box plot
-No

Front 37

Can we assess 3 variables?

Back 37

No not yet

Front 38

How do you assess one dichotomous and one continuous variable?

Back 38

-5 number summary, count and mean
-Histogram or box plot
-We can sample