Statistics

Statistics

When we look at our original histogram:

It has a bell shape to it. The bell shape is drawn in, and as students, you are probably familiar with bell curves for grading! Our histogram has equal distribution and a perfect bell. You can see that the circled green and blue boxes values fall under the bell. Remember they were the lowest frequencies observed in our data set. It is common to refer to these values as the 5% above the curve (green box) and the 5% below the curve (blue box). It is important to note that histograms can be skewed. Meaning there may not be a lower or upper 5% region under the bell curve. Think to a real life example, maybe you were in a class where one person received an 80 and everyone else had a grade below 80. The opposite is also true. What would the histogram look like if one person received an 80 and everyone else received a 90 or greater. We will talk more about distributions in Chapter 5.

• Table: It is also common to represent data in the form of a table. A table is created as a quick way to visualize quantitative data to qualitative categories.

Students

Number of Students

Average Exam Score

Male

12

97

Female

15

98

Above is a very simple table. What are we comparing? The table shows male student versus female student exam scores. We are also given the number of male and female students. What is our qualitative data? Gender is the qualitative or category data, male versus female. What are the quantitative measurements? The number of students and average exam score is the quantitative values. Remember, quantitative data is numerical. Qualitative data, by itself, is not numerical.

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