Learning Target: I can describe the shape of a data distribution and use it to draw conclusions. Learning Target: I can describe the shape of a data distribution and use it to draw conclusions.
Graphing Data
When data is graphed, we can see the shape or distribution of the overall responses.
Bell Curve
Some data will form a bell curve when it is graphed. (The overall shape looks like a bell.) In this type of shape, most of the responses cluster around the center. They taper off at either end.
The mean is at the center of the bell curve. Half of the data is distributed to the right and half of the data is distributed to the left.
Example
The line plot below is a visual representation of data. It shows the shoe sizes for a group of students in middle school.
The overall distribution of the data could be described as a bell curve.
Skewed Data
Skewed data has a spread of data, or a "long tail," to one side or the other.
Left Skew
A left skew, or negative skew, has a long tail to the left.
Right Skew
A right skew, or positive skew, has a long tail to the right.
Let's Practice Together
Label each graph below as either bell curve, right-skewed, or left-skewed.
1.
Your Turn
2.
3.
Check for Understanding
1. If you collect data, and the numbers cluster around the higher values while spreading out thinner over the lower values, how is the data skewed?
Answers
1. left-skewed
2. bell curve
3. right-skewed
Check for Understanding
1. left-skewed
