Prepare a table of a grouped frequency distribution of test scores with columns for class interval, frequency, cumulative frequency, percentage, cumulative percentage/percentile rank, z-score, and T-score. Explain this table in your own words so that a lay person could understand it.
Begin by ordering the 10 test scores in our example data set from lowest to highest to make them easier to work with: 7, 7, 10, 10, 11, 12, 13, 14, 15, 15. (The fact that each score was out of a possible 20 points is not relevant when making a frequency table, unless you want to include rows for all possible test scores to include those below 7 and above 15, which would be unusual.) Using class intervals means that each row of your table represents a range of scores, in this case 2, so that the first row of your column of scores is 7-8, the second is 9-10, and so on. The next column contains the frequencies, which is the number of scores on the test that are in each class interval. If you look at the scores we ordered from lowest to highest, you can easily see that only 2 scores are in the first class interval of 7-8, the 2 scores of 7. The next class interval of 9-10 also has a frequency of 2, because only the 2 scores of 10 ...
This solution provides a detailed step-by-step explanation of how to make a table of a grouped frequency distribution from raw data. It explains how to find and compute the values to include under columns for class interval, frequency, cumulative frequency, percentage, cumulative percentage/percentile rank, z-score, and T-score. The instructions are provided in the context of an example that walks you through the steps for creating a table of a grouped frequency distribution from a data set of 10 test scores (ranging from a possible 0 to 20) using a class interval of 2. It concludes with a recommendation for how to provide an explanation of how to interpret the table in a way that a layperson could easily understand. Internet links are provided.