Midterm Practice Flashcards by Kayla Chingman

Numerical variables can be subdivided into which two types?

Discrete and Continuous

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Cross-Sectional data are observations:

coming from different individuals or groups at a single point in time

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“Number of children” is a:

Discrete variable

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SPX daily closing prices during 6/1/2019 - 12/15/2019 are:

Time Series Data

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What is an example of a population?

The number of cars sold in Michigan

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The statement “categorical variables can be classified as either discrete or continuous” is:

False

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Suppose we are interested in political affiliation, a categorical variable that might assume three values - Republican, Democrat, or Independent. How many dummy variables should be constructed to represent political affiliation?

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A variable is classified as ordinal if:

There is a natural ordering of categories

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What is an example of a sample?

Participants in an experiment

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Panel Data are:

Derived from a number of observations over time on a number of cross-sectional units

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What is an example of a nominal variable?

Color

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Time Series Data are observations:

Collecting at usually discrete and equally spaced time intervals

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Player Salary Data for 10 MLB baseball teams during 2012-2019 is an example of what type of data?

Panel Data

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To represent a categorical variable with K different categories, the number of dummy variables needed is:

K-1

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The location of a normal distribution is determined by:

The mean

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Population Definition

All of the entries of interest in a study

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Population Example

All drivers in Michigan

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Sample Definition

A subject (part) of the population

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Variable Definition

A characteristic of members of a population

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Observation Definition

A list of all variable values for a single member of a population

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Data Set Definition

A rectangular array of data with variables in columns and observations in rows

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What are the two types of data?

Numerical and Categorical

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Numerical Data is:

Meaningful arithmetic can be performed (Age)

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Numerical Data’s Two Subcategories are:

Discrete and Continuous

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Categorical Data is:

Non-numerical (Gender)

Categorical Data's Two Subcategories are:

Ordinal and Nominal

Ordinal Data is used when:

Order is important (Ranking)

Discrete Data is used when:

The number of values is countable (Number of Children)

Nominal Data is used when:

There is no natural order (Gender)

Continuous Data is used when:

The number of values is uncountable (Time)

How many types of data are there?

What are the 3 types of data?

Cross-sectional, Time-series, and Panel

Panel Data is:

Data derived from a number of observations over time on a number of cross-sectional units

Panel data is a combination of what two types of data?

Cross-sectional and Time-series

Normal Distribution is:

A continuous probability distribution that has a bell-shaped probability density function (pdf)

Normal Distribution Formula

F(X) = 1/[sqrt(2*pi*s.d.)^(e-(x-µ)^2/(2s.d.^2)]

In normal distribution the pdf moves which way when µ gets larger?

Rightward

In normal distribution the standard deviation determines:

The shape

In normal distribution when the standard deviation gets larger, the pdf does what?

Gets flatter

T-Distribution is:

A continuous probability distribution that has a bell-shaped pdf, like the normal distribution, but has fatter tails

What defines the shape of the t-distribution?

The degrees of freedom (df)

The Degrees of Freedom (df) are:

n-1

When df gets larger, the t-distribution:

Approaches to the Z-distribution

F-Distribution is:

A continuous, positively skewed probability distribution determined by two parameters, d1 (d1 = n1-1), d2 (d2 = n2-1)

What defines the shape of the F-Distribution?

The degrees of freedom (d1, d2)

The F-Distribution is non-negative, meaning it must have a minimum value of:

Permutation is:

Any arrangement of r objects selected from a single group of n possible objects (when order is important)

Combination is:

Any arrangement of r objects selected from a single group of n possible objects (when order isn't important)

Sample Random Sampling is:

Each possible sample of size n has the same chance of being chosen

What are the 4 types of sampling?

Sample Random, Systemic, Stratified, and Cluster

Hypothesis Testing is:

A procedure based on sample evidence and probability theory to determine whether the hypothesis is a reasonable statement

Null Hypothesis is:

A statement that is tested (Ho)

Alternative Hypothesis is:

A statement that is accepted if the sample data provide sufficient evidence that the null is false (H1)

A test is one-tailed if:

H1 states a direction

A test is two-tailed if:

H1 does not state a direction

Type 1 Error is:

Rejecting a null when it is true

Type 2 Error is:

Failing to reject a null when it is fake

The significance level is:

The probability of making a Type 1 error, α (alpha)

The critical value is:

The dividing point between the region where the null is rejected and the region where it is not rejected

The P-Value is:

A probability that measures the strength of evidence in support of the null. The null is often rejected when the P-Value is less than the significance level

The colleges, such as college of business admin, college of arts and media, and college of education at CMU are:

Nominal

The sample is 5,8,7,10,13,6,9,11,12. To test whether the population mean is 10, we apple what type of test?

T test

For a one sample z-test, when the calculated z value is smaller than the critical z value in absolute value, we:

do not reject the null