Unit 4: Graphs, data and loans

3 dot points across 3 inquiry questions, in syllabus order. Each dot point has a focused answer, with exam-style questions and worked answers where available.

Bivariate graphs

Construct and interpret scatterplots of two numerical variables, identify the explanatory and response variables, describe the form, direction and strength of an association, draw a line of best fit by eye, and use it to make and judge predictions

How to plot bivariate data on a scatterplot, choose the explanatory and response variables, describe association by direction, form and strength, draw a line of best fit by eye, use it to predict (interpolation and extrapolation), and explain why association is not causation.

7 min read →

Summarising and comparing data

Calculate and interpret the mean, median, mode and range of a data set, identify outliers and their effect, display and compare two or more data sets using back-to-back stem plots, dot plots and column graphs, and make decisions supported by the data

How to summarise data with the mean, median, mode and range, recognise outliers and choose the best measure of centre, and compare two data sets with back-to-back stem plots, dot plots and side-by-side column graphs to make a supported decision.

7 min read →

Loans and compound interest

Calculate simple and compound interest, use the compound interest formula and tables or spreadsheets, compare loan and credit options including personal loans, car loans and credit cards, and calculate the total cost of a loan including interest and fees

Simple interest versus compound interest, using the compound interest formula for different compounding periods, how reducing-balance loans and credit cards work, and how to compare loans by total repayments, interest and fees to make an informed borrowing decision.

8 min read →