Year 8 Science · Unit 4 · Lesson 5
Challenge Worksheet
Learning Goals
Read the graph
Germination rate (%) of four Australian plant species in three soil types
Data: simulated data based on Australian native plant propagation research (CSIRO Plant Industry, 2019).
(a) Which species–soil combination produced the highest germination rate? Estimate its value.
(b) A student suggests replacing this grouped bar chart with a line graph. Would a line graph work here? Explain why or why not.
(c) Describe one improvement that would make this graph's design clearer or more accurate.
Design a graph from scratch
Investigation
A Year 8 student is investigating the relationship between hours of sleep and reaction time. They collected data from 25 students: sleep ranged from 4 to 9 hours per night, and reaction time ranged from 180 ms to 350 ms. Students who slept more tended to respond faster.
Use the four response boxes below to fully design this graph.
(a) Which graph type would you use, and why is it the best choice for this kind of data?
(b) Which variable should go on the x-axis (horizontal) and which on the y-axis (vertical)? Justify your choices.
(c) What would a "line of best fit" on this graph show? How is it different from connecting every dot?
(d) If the graph showed a strong negative correlation, what conclusion could the student draw? What would the graph look like?
Wrap Up
In one sentence, what was the main idea of this lesson?