# Differentiate between parametric and nonparametric tests

Differentiate between parametric and nonparametric tests

Identify the data in the situations A-G as:

+ Numeric or Attribute Data

+ Parametric or Nonparametric

+ Briefly explain you choice

Complete any four.

Example: A manufacturer produces a batch of memory chips and measures the mean-time-between-failure (MTBF). The manufacturer then changes a manufacturing process and produces another batch and again measures the MTBF. Did the change to the process improve the MTBF?

Numeric Data

Parametric

Explain you choice - The MTBF is time measured in hours. Samples are taken before and after the process was changed. This may be treated as dependent data with the intervention as the process change. This assumes that the data is normally distributed.

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A. From a written survey where the respondents were asked to rate an individual on a Likert scale of 1 to 5. One group rated an individual a 3.7, another group rated the individual a 4.3. Is the difference statistically significant between the two groups?

Numeric or Attribute Data

Parametric or Nonparametric

Explain you choice

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B. Do students work longer hours to pay for newer cars? The survey contained two fill-in-the-blank questions. (1) About how many hours per week do you expect to work at an outside job this semester? (2) What is the age (in years) of the car you usually drive? The researcher collected 162 responses. Neither variable was normally distributed and there were outliers.

Numeric or Attribute Data

Parametric or Nonparametric

Explain you choice

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C. Jim Smith owns three real estate offices in Anytown. He has decided to open one more office, but he cannot decide between Hometown or Uptown as the town where he wants to locate. He will be comparing the mean number of homes sold per real estate agent, and the mean commission percentage earned by agents in the two towns to make his decision.

Numeric or Attribute Data

Parametric or Nonparametric

Explain you choice

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D. A study to determine if job absenteeism is distributed evenly over the week.

Numeric or Attribute Data

Parametric or Nonparametric

Explain you choice

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E. A market analyst wished to see whether consumers have any preference among five flavors of a new fruit soda. A sample of 100 people provided these data: Cherry 32, Strawberry 28, Orange 16, Lime 14, and Grape 10. Is there enough evidence to reject the claim that there is no preference in the selection of fruit soda flavors?

Numeric or Attribute Data

Parametric or Nonparametric

Explain you choice

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F. Sally's Beauty Salon just opened for business. Sally assigns the stylists customers on a rotation basis so that everyone is kept busy all day. One month after she opened the salon, Sally's customer count for each stylist was (a) 20 customers; (b) 30 customers; (c) 15 customers; and (d) 25 customers. Has Sally been fair in how she allocates customers to each of the stylists?

Numeric or Attribute Data

Parametric or Nonparametric

Explain you choice

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G. A comparison of salaries between male and female employees in the same organization.

Numeric or Attribute Data

Parametric or Nonparametric

Explain you choice

https://brainmass.com/statistics/nonparametric-tests/differentiate-between-parametric-and-nonparametric-tests-225754

#### Solution Preview

Numeric data is data that is measured in numbers (height, weight, money, temperature, etc.). Attribute data is data that is assigned to categories (color, gender, etc.).

Parametric tests are used when the data is numeric AND when the data is normally distributed (symmetrical). If those criteria don't apply, then you use a non-parametric test. If the data is numerical, but is a ranking (i.e. something rated on a scale of 1 - 10), then you use a non-parametric test.

I'm using those facts to answer the following questions.

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A. From a written survey where the respondents were asked to rate an individual on a Likert scale of 1 to 5. One group rated an individual a 3.7, another group rated the individual a 4.3. Is the difference statistically significant between the two groups? ...

#### Solution Summary

The solution defines numeric/attribute data and parametric/nonparametric tests. It explains when to use parametric and nonparametric tests and for each of the problems A to G, identifies the data as numeric or attribute and explains why to you would use a parametric or nonparametric test.