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Univariate data

Student learning objectives

  • The student will design and carry out a survey.
  • The student will analyze and graphically display the results of the survey.

Instructions

As you complete each task below, check it off. Answer all questions in your summary.
____ Decide what data you are going to study.

Here are two examples, but you may NOT use them: number of M&M's per bag, number of pencils students have in their backpacks.


____ Are your data discrete or continuous? How do you know?
____ Decide how you are going to collect the data (for instance, buy 30 bags of M&M's; collect data from the World Wide Web).
____ Describe your sampling technique in detail. Use cluster, stratified, systematic, or simple random (using a random number generator) sampling. Do not use convenience sampling. Which method did you use? Why did you pick that method?
____ Conduct your survey. Your data size must be at least 30.
____ Summarize your data in a chart with columns showing data value, frequency, relative frequency and cumulative relative frequency.
Answer the following (rounded to two decimal places):
  1. x ¯ = _____
  2. s = _____
  3. First quartile = _____
  4. Median = _____
  5. 70 th percentile = _____
____ What value is two standard deviations above the mean?

____ What value is 1.5 standard deviations below the mean?
____ Construct a histogram displaying your data.
____ In complete sentences, describe the shape of your graph.
____ Do you notice any potential outliers? If so, what values are they? Show your work in how you used the potential outlier formula to determine whether or not the values might be outliers.
____ Construct a box plot displaying your data.
____ Does the middle 50% of the data appear to be concentrated together or spread apart? Explain how you determined this.
____ Looking at both the histogram and the box plot, discuss the distribution of your data.

Assignment checklist

You need to turn in the following typed and stapled packet, with pages in the following order:

  • Cover sheet : name, class time, and name of your study
  • Summary page : This should contain paragraphs written with complete sentences. It should include answers to all the questions above. It should also include statements describing the population under study, the sample, a parameter or parameters being studied, and the statistic or statistics produced.
  • URL for data, if your data are from the World Wide Web
  • Chart of data, frequency, relative frequency, and cumulative relative frequency
  • Page(s) of graphs: histogram and box plot

Continuous distributions and central limit theorem

Student learning objectives

  • The student will collect a sample of continuous data.
  • The student will attempt to fit the data sample to various distribution models.
  • The student will validate the central limit theorem.

Instructions

As you complete each task below, check it off. Answer all questions in your summary.

Part i: sampling

____ Decide what continuous data you are going to study. (Here are two examples, but you may NOT use them: the amount of money a student spent on college supplies this term, or the length of time distance telephone call lasts.)
____ Describe your sampling technique in detail. Use cluster, stratified, systematic, or simple random (using a random number generator) sampling. Do not use convenience sampling. What method did you use? Why did you pick that method?
____ Conduct your survey. Gather at least 150 pieces of continuous, quantitative data .
____ Define (in words) the random variable for your data. X = _______
____ Create two lists of your data: (1) unordered data, (2) in order of smallest to largest.
____ Find the sample mean and the sample standard deviation (rounded to two decimal places).

  1. x ¯ = ______
  2. s = ______
____ Construct a histogram of your data containing five to ten intervals of equal width. The histogram should be a representative display of your data. Label and scale it.

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Source:  OpenStax, Introductory statistics. OpenStax CNX. May 06, 2016 Download for free at http://legacy.cnx.org/content/col11562/1.18
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