Chapter 02

This is a chapter that requires you to perform operations with your data. You need to understand the concepts, but you also need to be able to perform the operations.

The concepts to understand:

  • raw score
  • outlier
  • N
  • simple frequency distribution
  • percentage distribution
  • relative frequency and proportion of area under the normal curve
  • cumulative frequency
  • percentile
  • normal distribution—what is it? can you graph one? what are the features of a normal distribution? Can you identify the raw score (the location on the X axis) that would be the 50th percentile? Where are the scores that are the 20th and 80th percentiles?
  • skew—define and draw graphs of negative skew and positive skew
  • be able to recognize, give, and/or interpret examples of skewed distributions
  • bimodal distribution
  • histograms
  • floor effect and ceiling effect

Now, perform some operations to practice. Use the following data set to create a simple frequency distribution,  a relative frequency and percentage distribution, cumulative frequency distribution, and percentiles. (Put all of these in the same table.)

Then draw a histogram of the simple frequency distribution.

Data: Researchers asked people to answer “how many dollars do you have in your wallet right now?” Here were the answers:

3, 10, 5, 1, 10, 5, 2, 5, 7, 5


Do the odd numbered problems and check your answers, for more practice.

Be able to perform and interpret any SPSS procedures that we do for this chapter.