Statistics : Skewed Distributions

Study concepts, example questions & explanations for Statistics

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Example Questions

Example Question #1 : Descriptive Statistics

A social scientist performs an experiment testing the frequency and correlation of several demographics. She plots a histogram measuring income versus education level. She produces the following graph:

 Skewedright

Which of the following choices best describes this model?

Possible Answers:

Left Skewed

Uniform

None of these

Bimodal

Right Skewed

Correct answer:

Right Skewed

Explanation:

In order to solve this problem let's review the following distributions: normal, positive/right skewed, negative/left skewed, bimodal, and uniform.

Normal Distribution:

Normal

A normal distribution is also known as a bell curve. Data that form a bell curve have three primary characteristics: the data is single peaked meaning that it has a single mode, it is symmetrical, and contains no outliers.

 

Positive/Right Skewed Distribution

Skewedright

A positive or right skewed distribution has a longer tail on the right side due to outliers while the majority of the points are concentrated on the left side of the graph. In other words, the set favors probabilities on the left of the model.

 

Negative/Left Skewed Distribution

Skewedleft

A negative or left skewed distribution has a longer tail on the left side due to outliers while the majority of the points are concentrated on the right side of the graph. In other words, the set favors probabilities on the right of the model.

 

Bimodal Distribution 

Bimodal

In a bimodal distribution, there are two peaks due to several modes in the data set. These multiple central tendencies are the result of two or more favorable probabilities in the set.

Uniform Distribution

Uniform

In a uniform distribution the data points form a a rectangle. These models are formed when data points possess a constant probability.

The model in the question matches that or a positive or right skewed distribution; therefore, the correct answer is "right skewed."

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