A survey was conducted by 'City Fitness Magazine' to determine the average weekly exercise duration of the city's population. The magazine distributed questionnaires only to subscribers who visited the magazine's dedicated website forum, which focuses on advanced training techniques.
The results showed that the average subscriber exercised 8.5 hours per week, and the magazine published a headline: "City Residents Exercise 8.5 Hours Weekly!". This data was presented in a bar chart where the y-axis started at 7.0 hours, making the difference between 8.0 hours and 9.0 hours look visually massive compared to if the axis started at zero.
a) Assess the representativeness of the sample compared to the claim made about 'City Residents'.
b) Evaluate how the presentation of data (the bar chart y-axis starting at 7.0 hours) might mislead the reader.
Write your answer out first, then check it against the worked solution.