Dot Plot Worksheet PDF | PDF - Free Printable

Let’s solve each problem step by step.

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Problem 1: Siblings Dot Plot

We are given a dot plot showing how many siblings students have. Each dot represents one student.

The number line goes from 0 to 6 (number of siblings). We count the dots above each number.

- Above 0: 3 dots → 3 students have 0 siblings
- Above 1: 3 dots → 3 students have 1 sibling
- Above 2: 3 dots → 3 students have 2 siblings
- Above 3: 5 dots → 5 students have 3 siblings
- Above 4: 4 dots → 4 students have 4 siblings
- Above 5: 0 dots → no students have 5 siblings
- Above 6: 1 dot → 1 student has 6 siblings

Now answer the questions:

a. How many students have six siblings?
→ Look at “6” on the number line. There is 1 dot.
✔ Answer: 1

b. How many students have no siblings?
→ “No siblings” means 0 siblings. Look at “0”. There are 3 dots.
✔ Answer: 3

c. How many students have three or more siblings?
→ That means 3, 4, 5, or 6 siblings.
Add the dots above 3, 4, 5, and 6:
- 3 siblings: 5 dots
- 4 siblings: 4 dots
- 5 siblings: 0 dots
- 6 siblings: 1 dot
Total = 5 + 4 + 0 + 1 = 10
✔ Answer: 10

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Problem 2: Pulse Rates Line Plot

This is a line plot with X’s instead of dots. Each X represents one boy. The numbers below are pulse rates.

List out the data by counting X’s above each number:

- 79: 2 X’s → 2 boys
- 80: 3 X’s → 3 boys
- 81: 1 X → 1 boy
- 82: 3 X’s → 3 boys
- 83: 4 X’s → 4 boys
- 84: 0 X’s → 0 boys
- 85: 2 X’s → 2 boys

Total boys: 2+3+1+3+4+0+2 = 15? Wait — the problem says 16 boys. Let me recount carefully.

Looking again at the plot description:

It says:
“X
X X
X X X X X
X X X X X X”

Wait — let’s map it properly based on alignment under numbers 79 to 85.

Assuming the X’s are aligned as:

Under 79: two X’s (bottom row and one above) → actually, looking at typical layout:

Probably:

- 79: 2 X’s (one in bottom row, one above)
- 80: 3 X’s (bottom, middle, top)
- 81: 1 X (only bottom)
- 82: 3 X’s (bottom, middle, top? But wait — let's list positions)

Actually, better to count total X’s first.

From the text representation:

Line 1 (top): X at 80 and X at 83 → that’s 2
Line 2: X at 80, X at 82, X at 83 → that’s 3
Line 3: X at 79, X at 80, X at 82, X at 83, X at 85 → that’s 5
Line 4 (bottom): X at 79, X at 80, X at 81, X at 82, X at 83, X at 85 → that’s 6

Wait — this is messy. Let me interpret the diagram as written:

The user wrote:

```
X X
X X X
X X X X X
X X X X X X
79 80 81 82 83 84 85
```

So aligning vertically:

Above 79: two X’s (third and fourth lines) → 2
Above 80: four X’s? Let’s see:

Row 1 (top): only above 80 and 83 → so 80 gets one, 83 gets one
Row 2: above 80, 82, 83 → so 80: second, 82: first, 83: second
Row 3: above 79, 80, 82, 83, 85 → 79: first, 80: third, 82: second, 83: third, 85: first
Row 4 (bottom): above 79, 80, 81, 82, 83, 85 → 79: second, 80: fourth, 81: first, 82: third, 83: fourth, 85: second

So now count per column:

- 79: rows 3 and 4 → 2
- 80: rows 1,2,3,4 → 4
- 81: row 4 only → 1
- 82: rows 2,3,4 → 3
- 83: rows 1,2,3,4 → 4
- 84: none → 0
- 85: rows 3 and 4 → 2

Total: 2+4+1+3+4+0+2 = 16 ✔ matches the problem statement.

So corrected counts:

- 79: 2
- 80: 4
- 81: 1
- 82: 3
- 83: 4
- 84: 0
- 85: 2

Now answer the questions:

a. What is the range of the pulse rates?
Range = highest value - lowest value
Highest pulse rate: 85
Lowest pulse rate: 79
Range = 85 - 79 = 6

✔ Answer: 6

b. How many boys had a pulse rate over 81?
“Over 81” means greater than 81 → so 82, 83, 84, 85
Count boys at those rates:
- 82: 3 boys
- 83: 4 boys
- 84: 0 boys
- 85: 2 boys
Total = 3 + 4 + 0 + 2 = 9

✔ Answer: 9

c. How many boys had a pulse rate of 83?
Look at 83: we counted 4 boys.

✔ Answer: 4

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Final Answer:

1. a. 1
b. 3
c. 10

2. a. 6
b. 9
c. 4