This is a trick question because the data displays two modes: both 9 and 2 are correct. If you selected 9 you are correct if you selected 2 you are also correct. Notice that the frequency distribution only lists those scores that were actually attained by students, not all the possible scores. Illustration 9: Elementary Class Frequency Distribution Student Score
The frequency distribution for the class is listed in Illustration 9. Let’s complicate the process by looking at the data collected from an elementary class where 14 students were given the same 10 point quiz. It simply means the data does not indicate a normal distribution of data that would create a normal curve when graphed. Also note that non-normal does not imply that it is incorrect. Both cases are examples of non-normal data distributions. Note that the mode moves to the left on a positively skewed distribution and to the right on a negative skewed distribution.
Again, the highest point indicates the score with the greatest frequency. This represents the greatest frequency of that score.įrom Illustration 8: Mode of Skewed GraphsĪs expected, the mode is located at the highest point on both the positively and negatively skewed graph. Note that the mode is located at the highest point of the graphed data. Let’s examine several examples to further understand the concept of mode by locating it on three representative types of graphs.įrom Illustration 7: Mode of a Normal Curve The mode is easy to locate on any type of distribution curve graph, regardless of skewing. Why is the mode 89? Because there were four students who scored an 89, and that was the largest number of students who scored at the same level on this assessment. If the data are arranged in a frequency distribution similar to illustration 4, then the mode is easy to identify. The mode is defined as the most frequently occurring score. The next section describes each statistic and both its educational value and its limitations. Each of these statistics can be a good measure of central tendency in certain situations and an inappropriate measure in other scenarios. These measures of central tendency are defined differently because they each describe the data in a different manner and will often reflect a different number. All three provide insights into “the center” of a distribution of data points. Knowing the center point answers such questions as, “what is the middle score?” or “which student attained the average score?” There are three fundamental statistics that measure the central tendency of data: the mode, median, and mean. One of the most useful statistics for teachers is the center point of the data. This lesson will introduce the following measures of central tendency (the center points of data) and variability (the diversity of the data). The accompanying video will review statistical concepts and calculations. In this workshop, you will develop the ability to identify the educational significance of statistics and to interpret and apply useful statistics for the classroom. ⬅ Previous Lesson Workshop Index Next Lesson ➡ Measures of Central Tendency and Variability Objective