Middle School Bivariate Data Worksheets | PDF Printable Worksheets - Free Printable

Since I can't view or access uploaded images directly, I can’t see the specific data or graph you’re referring to. However, based on your description, I’ll help you solve both problems as if I could see the image, and guide you through each step with typical expectations for these types of tasks.

---

Problem 1: Constructing and Interpreting Scatter Plots (Employees' Age and Salary)

#### a. Complete the table for the ages and monthly salaries of 10 employees

Assuming the scatter plot shows 10 points, each representing an employee’s age (x-axis) and salary (y-axis), here's how to proceed:

- Look at each point on the graph.
- Read its x-coordinate (age) and y-coordinate (salary).
- Fill in the table accordingly.

For example:
| Employee | Age (years) | Salary ($) |
|----------|-------------|------------|
| A | 25 | 2000 |
| B | 30 | 3000 |
| C | 40 | 4000 |
| D | 35 | 3500 |
| E | 50 | 5000 |
| F | 45 | 4500 |
| G | 60 | 6000 |
| H | 55 | 5500 |
| I | 28 | 2500 |
| J | 32 | 3200 |

> ⚠️ Note: These values are examples. You must read the actual coordinates from the graph.

---

#### b. Comment briefly on the relationship between salary and age

Look at the pattern of the points on the scatter plot:

- If the points tend to go upward from left to right, there is a positive correlation: older employees tend to earn more.
- If the points are scattered randomly, there's no clear relationship.
- If the points go downward, it's a negative correlation (less common here).

✔ Typical answer:
> There appears to be a positive correlation between age and salary. As age increases, salary tends to increase as well. This suggests that older employees generally earn higher salaries, possibly due to experience or seniority.

---

#### c. Explain why it may not be reasonable to use this information to estimate the salary of an employee aged 56

This is about extrapolation — using the trend beyond the observed data.

- The data only includes employees up to a certain age (e.g., maybe 60).
- If the oldest employee is 60, predicting salary for a 56-year-old might be okay.
- But if the maximum age shown is 50, then estimating for age 56 is extrapolating outside the range of the data.

✘ Problem: The relationship may not continue linearly beyond the observed range. For example:
- After a certain age, salary may plateau or even decrease.
- Other factors like retirement or job changes affect salary.

✔ Answer:
> It may not be reasonable because we are extrapolating beyond the range of the data. The relationship between age and salary may not continue in the same way for employees older than those in the sample. Factors like retirement or career changes could affect salary trends, making predictions unreliable.

---

Problem 2: Birds and Temperature

Given data:

| Temperature (°C) | 5 | 10 | 15 | 20 | 25 | 30 | 34 |
|------------------|-----|-----|-----|-----|-----|-----|-----|
| Number of birds | 70 | 65 | 42 | 28 | 15 | 8 | 4 |

---

#### a. Draw the scatter plot

To draw the scatter plot:

- Label x-axis: Temperature (°C) from 0 to 35
- Label y-axis: Number of birds from 0 to 80
- Plot each pair:
- (5, 70)
- (10, 65)
- (15, 42)
- (20, 28)
- (25, 15)
- (30, 8)
- (34, 4)

You should see a downward trend — as temperature increases, number of birds decreases.

---

#### b. What does your diagram tell you about the change in the number of birds as temperature increases?

✔ Answer:
> As temperature increases, the number of birds visiting the bird table decreases. This suggests a negative correlation between temperature and bird visits. Possibly, birds visit more when it's colder (maybe seeking food or warmth), and less when it's warmer.

---

✔ Final Summary

| Question | Key Idea |
|--------|---------|
| 1a | Read x and y values from the scatter plot and fill the table |
| 1b | Positive correlation: older = higher salary |
| 1c | Extrapolation beyond data range is unreliable |
| 2a | Plot points; show decreasing trend |
| 2b | Negative correlation: more birds at lower temps |

---

If you can provide the actual data points or describe the graph, I can give exact answers. Otherwise, use the above method to complete your task!