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Distribution of a Variable - Essay Example

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The paper "Distribution of a Variable" tells us about a variable is a description of the relative number of times each possible outcome will occur in a number of trials. Categorical variables should be displayed using pie charts or bar graphs…

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Subject: Statistics
Type: Essay
Level: Masters
Pages: 3 (750 words)
Downloads: 2
Author: branson53

Extract of sample "Distribution of a Variable"

What does the distribution of a variable (or data set) refer to?

It refers to the way its values are spread over all possible values

Wbat is the Mean of a data set, and how would you calculate it?

It refers to the average value of the dataset

What is the median of a data set, and how do you calculate it?

Refers to the middle value in the sorted data set. It is obtained by sorting the data and getting the middle term if number values is odd and averaging middle values if the number of values is even

What is the mode of a data set, and how do you calculate it?

Refers to the most common value or a group of values in a distribution

What is an outlier in a data set?

An outlier is a data value that is much higher or much lower than almost all of the other values

What measures of central tendency does an outlier effect?

The mean

What is average confusion?

Confusion of the exact mean caused by presence of outliers in a given data set

Draw an example of single mode data set.

Draw an example of a bimodal data set.

Draw an example of a data set that is skewed left.
Draw an example of a data set that is symmetrical.

When does the median represent a data set better than the mean?

When there are many outliers

Chapter 6 section B

What is the range of a set of data?

Refers to the difference between the highest and the lowest data values of a given data set

What is another name for the lower quartile?

The first quartile

What is the lower quartile?

It divides the lower fourth of the data set from the upper three fourths

What are the other two names for the middle quartile?

The median, the second quartile

What is the middle quartile?

It refers to the overall median term of a given data set

What is another name for the upper quartile?

Third quartile

What is the upper quartile?

It is the median of the data values in the upper half of a data set

What is the 5 number summary of a set of data?

low value, lower quartile, median, upper quartile, high value

What is a box plot?

Refers to plot that shows the five number summary visually with a rectangular box enclosing the lower and upper quartiles, a line marking the median and whiskers extending to the minimum and maximum values.

The term standard deviation sounds really scary, but it is not really a horrible monster what is it a measure of?

It is a measure of spread or variation

What is the formula we use to find the standard deviation of a set of data?
What is the range rule of thumb?

It is the relationship between the standard deviation and the range given by

How do we use the standard deviation to estimate the high and low values of a data set?

Chapter 6 Section C

What does the phrase normal distribution refer to?

Refers to symmetric, bell-shaped distribution with a single peak. Its peak corresponds to the mean, median, and the mode of the distribution.

What criteria does a set of data need to have for it to likely be a normal distribution?

Most data values are clustered near the mean, giving the distribution a well-defined single peak.

Data values are spread evenly around the mean, making the distribution symmetric.

Larger deviations from the mean are increasingly rare, producing the tapering tails of the distribution.

Individual data values result from a combination of many different factors

Explain the 68-95-99.7 rule.

About 68% of the data points fall within 1 standard deviation of the mean, about 95% data points fall within 2 standard deviation points of the mean and about 99.7% of the data points fall within 3 standard deviation points of the mean.

What is another name for a standard score?

z-sore

What is a standard score a measure of?

It is a measure of the standard deviations above or below the mean.

How do you calculate a standard score?
What is a percentile (or percentile score) of a data value?

Refers to the percentage of all data values in a data set that are less than or equal to it

What does a percentile score of 23 mean?

A score of 80.23 percentile means that that score is better than 80.23% of all the scores.

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