Question 1: In a dual bar chart, Group A has 45 students and Group B has 30 students. Calculate the difference in the number of students between the two groups.

Answer: 15

Question 2: A dual bar chart shows the number of cars sold by two dealerships. Dealership X sold 120 cars, and Dealership Y sold 85 cars. What is the percentage increase in sales from Y to X?

Answer: 41.18

Question 3: A student reads a dual bar chart where the scale is labeled in groups of 20. The bar for Group C reaches the 60 mark, but the student reports 50. What common mistake might this student be making?

Answer: Misreading the scale or not counting correctly

Question 4: Construct a dual bar chart to compare the number of students who prefer different subjects: Math (40), Science (55), and History (35). Use the grid to draw the bars.

Answer:

Question 5: A dual bar chart shows the sales of two products over four months. In January, Product A sold 80 units, Product B 60 units. In February, Product A sold 70 units, Product B 75 units. Which product showed a greater overall increase in sales from January to February?

Answer: Product B

Question 6: A dual bar chart shows the number of votes for two candidates. Candidate X received 200 votes, Candidate Y 250 votes. The bars are scaled such that 1cm = 50 votes. What is the length of the bar for Candidate Y?

Answer: 5cm

Question 7: Explain why comparing heights alone can sometimes be misleading when analyzing dual bar charts. Provide an example of a potential mistake.

Answer: Ignoring scale differences or scale labels can lead to incorrect comparisons

Question 8: A dual bar chart shows two groups with bars at 60 and 40 units respectively. The scale is in 10s. What is the difference in their data values?

Answer: 20

Question 9: In a dual bar chart comparing two departments' sales, the bars are drawn with the same height, but the labels for the axes are different. One shows total sales, the other average sales per employee. Why might this cause confusion when comparing?

Answer: Different metrics (total vs. average) can lead to misleading comparisons

Question 10: A dual bar chart shows Group A with 70 responses and Group B with 55 responses. If the scale is in 10s, but the bars are drawn at 7cm and 5.5cm respectively, what mistake might the student have made?

Answer: Incorrect scale interpretation or misreading the scale

Question 11: Identify and correct the mistake in the following statement: 'The bar for Group A is taller than Group B, so Group A has more members.'

Answer: The mistake is assuming height directly equals quantity without checking the scale; they should compare scaled data, not just bar height.