Let’s solve for the
mean,
median,
mode, and
range of this data set:
Data:
72, 73, 79, 84, 84, 84, 90, 90, 97
---
Step 1: Mean (Average)
Add all numbers together, then divide by how many numbers there are.
Sum = 72 + 73 + 79 + 84 + 84 + 84 + 90 + 90 + 97
Let’s add step by step:
72 + 73 = 145
145 + 79 = 224
224 + 84 = 308
308 + 84 = 392
392 + 84 = 476
476 + 90 = 566
566 + 90 = 656
656 + 97 =
753
There are
9 numbers.
Mean = 753 ÷ 9 =
83.666... → We can write as
83.67 (rounded to two decimal places) or keep as fraction:
83 2/3
But since most school problems expect decimal, we’ll use
83.67
Wait — let me double-check that division:
9 × 83 = 747
753 - 747 = 6 → so 83 + 6/9 = 83 + 2/3 ≈
83.67
✔ Correct.
---
Step 2: Median (Middle Value)
The data is already in order from smallest to largest.
We have 9 numbers → middle one is the
5th number.
List with positions:
1: 72
2: 73
3: 79
4: 84
5:
84 ← median
6: 84
7: 90
8: 90
9: 97
So median =
84
✔ Confirmed.
---
Step 3: Mode (Most Frequent Number)
Look at which number appears most often.
- 72 → once
- 73 → once
- 79 → once
- 84 →
three times ← most frequent
- 90 → twice
- 97 → once
So mode =
84
✔ Confirmed.
---
Step 4: Range (Difference between highest and lowest)
Highest = 97
Lowest = 72
Range = 97 - 72 =
25
✔ Confirmed.
---
Final Answer:
Mean: 83.67, Median: 84, Mode: 84, Range: 25
Parent Tip: Review the logic above to help your child master the concept of mean median mode range definitions.
