Year 8 Science · Unit 4 · Lesson 10
Challenge Worksheet
Learning Goals
Read the scatter plot
Study the scatter plot below showing study hours (x-axis) versus test score (y-axis) for 12 students. Answer the four questions.
Data: hypothetical Year 8 cohort study, HSCScience.
(a) Identify the type of correlation shown in this scatter plot.
(b) The dashed line shows an approximate line of best fit. Use it to interpolate the expected test score for a student who studied for 6 hours.
(c) Identify the circled outlier. Suggest one specific reason why this student's result might not follow the general trend.
Evaluate this claim
A news article shows a graph of monthly ice cream sales alongside monthly drowning deaths across Australia over a full year. Both lines follow a very similar pattern — they rise together in summer (December–February) and fall together in winter (June–August). The article's headline reads: "Eating ice cream causes drowning — data proves it."
(a) Describe what the graph actually shows. Is the correlation real? What type is it?
(b) What confounding variable most likely explains why both ice cream sales and drowning deaths increase at the same time of year? Explain how this variable drives both.
(c) Explain, in your own words, why this article is a classic example of why "correlation does not equal causation."
(d) What type of evidence would be needed before a scientist could claim that eating ice cream causes drowning? Describe the key features of that evidence.
Wrap Up
In one sentence, what was the main idea of this lesson?