Lesson 2: Mean, Median, and Mode6.DS.4

I can…

I can find the mean, median, and mode of a data set.

Key words

• Mean — The average. Add all the numbers, then divide by how many there are.
• Median — The middle number when you put them in order.
• Mode — The number that shows up most often.
• Outlier — A number that is much bigger or smaller than the rest.
• Data distribution — How the data looks: where it sits and how spread out it is.
• Variability — How spread out the numbers are.

Steps

1. My small data set: 2, 4, 4, 6, 9. There are 5 numbers.
2. Mean: add them, 2 + 4 + 4 + 6 + 9 = 25, then divide by 5. So the mean = 25 ÷ 5 = 5.
3. Median: the numbers are already in order. The middle (3rd) value is 4, so the median = 4.
4. Mode: the number 4 appears twice, more than any other, so the mode = 4.

Try it

Data set: 4, 7, 10, 7, 12. What is the median?

Check your answer

7

Ordered: 4, 7, 7, 10, 12. The middle (3rd) value is 7.

Sentence starter

I know ___ because ___.

Goal: I can explain my reasoning using the words mean, median, mode, and outlier.