Measures of Variability/Central Tendency For Certain Categories

  • Thread starter Soaring Crane
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In summary, the question is asking about the types of data that can be used for central tendency and variability measures, with the options being nominal, ordinal, and continuous.
  • #1
Soaring Crane
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Homework Statement



Suppose that I have the following groups/categories with how each is measured next to them:

Response to light – measured on a scale of 1 to 4
HDL levels – continuous value from 1 to 100
Smoker status - smoker or non-smoker

The question is as follows:

What are the highest-level measures of central tendency and variability that can be used?



Homework Equations



If descriptive, equations would not apply.

The Attempt at a Solution



I know that central tendency includes mean, mode, and median and variability includes variance and standard deviation, but could someone please tell me what is meant by “highest-level measures”? Do I include the descriptive term (for example, central tendency answer "mean") or an actual measurement?

Thank you.
 
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  • #2
By “highest-level measures” I would assume that all the data is incorporated in the mean/variance estimate.

Solutions:

Answer 1: Use standard regression theory although the error terms (difference between fitted and observed) is not precisely normal (a mixture of dummy variables, categorical data and continuous). The Standard Error of Regression is the risk measure, the mean is given by the linear regression equation.

Answer 2: Use the error terms from answer 1 as an input to a Box-Cox Analysis of transformation. Use the proposed transformation on the y-variable to correct (or approximately adjust) for normality issues.

Answer 3: Use Least-Absolute deviations in place of a Least-Squares criteria. Apply risk measures (like average median deviation) and a median point estimate as discussed in the literature.
 
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  • #3
Soaring Crane said:

Homework Statement



Suppose that I have the following groups/categories with how each is measured next to them:

Response to light – measured on a scale of 1 to 4
HDL levels – continuous value from 1 to 100
Smoker status - smoker or non-smoker

The question is as follows:

What are the highest-level measures of central tendency and variability that can be used?



Homework Equations



If descriptive, equations would not apply.

The Attempt at a Solution



I know that central tendency includes mean, mode, and median and variability includes variance and standard deviation, but could someone please tell me what is meant by “highest-level measures”? Do I include the descriptive term (for example, central tendency answer "mean") or an actual measurement?

Thank you.

I'm not sure why the previous poster gave what he/she did - not relevant.
The question is essentially assessing your ability to determine the type of data that would be recorded. If the data is nominal (strictly categories) you wouldn't use mean or median for central tendency, nor would standard deviation qualify for variability. If the data is ordinal (can be arranged low to high) you could use median for central tendency. If the data were continuous (numerical) both mean and median would apply for central tendency, and standard deviation/variance for variability.
 

FAQ: Measures of Variability/Central Tendency For Certain Categories

What is the purpose of using measures of variability and central tendency for certain categories?

The purpose of using measures of variability and central tendency for certain categories is to summarize and describe the data in a meaningful way. These measures provide a better understanding of the distribution of data, the typical or average value, and the degree of spread or variation within the data.

What is the difference between measures of variability and central tendency?

Measures of variability, such as range and standard deviation, describe how spread out the data is. On the other hand, measures of central tendency, like mean and median, describe the center or average value of the data. They provide complementary information about different aspects of the data distribution.

How do you calculate the mean and median for categorical data?

To calculate the mean for categorical data, you can assign numeric values to the categories and then use the formula for calculating the mean. For example, if you have categories of "small," "medium," and "large" with values of 1, 2, and 3 respectively, the mean can be calculated as (1+2+3)/3 = 2. To calculate the median, you can arrange the data in order and find the middle value. If there is an even number of data points, take the average of the two middle values.

Can measures of variability and central tendency be used for non-numerical data?

Yes, measures of variability and central tendency can be used for non-numerical data, such as categorical data. In this case, the median and mode can be used as measures of central tendency, while range and interquartile range can be used as measures of variability.

How do outliers affect measures of variability and central tendency?

Outliers, which are extreme values in the data, can greatly affect the measures of variability and central tendency. For example, a large outlier can significantly increase the range and standard deviation, making them less representative of the majority of the data. Outliers can also affect the mean, pulling it towards the extreme value, while the median is less affected by outliers.

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