ITPEC IP October 2019 Question 21
When a spreadsheet application to create a line graph based on actual sales in the table below is used, the scale range of the vertical axis was automatically set between 0 and 1,500,000 yen. However, as the graph does not show clearly the change of sales over time, the change of sales needs to be more clearly shown without changing the frame size. Which of the following is the most appropriate chart editing operation?
Unit: Yen
Explanation
Change the display range of the vertical axis to 1,000,000–1,300,000 yen — narrowing the axis to the band the data occupies spreads the line over the frame.
All twelve months lie between 1,063,000 and 1,220,000 yen, a spread of 1220 − 1063 = 157 thousand yen. On a 0–1,500,000 axis that spread fills only about a tenth of the chart height, so the line looks almost flat. With the axis from 1,000,000 to 1,300,000 (a span of 300 thousand yen) every value still fits, and the same spread now fills about half the height, roughly five times as tall, in the same frame.
Answer (b)
Why not others:
- •(a) — changing the unit to thousand yen only relabels the axis; 0–1,500 thousand is the same range, so the line is exactly as flat
- •(c) — bars still start from zero on the same 0–1,500,000 axis, so twelve bars of nearly equal height show the change no better; a line graph is the usual chart for change over time
- •(d) — an average line adds a reference level but does not enlarge the vertical distance between the months
Key rule: A chart's apparent variation depends on the axis range: start the axis near the data to show small changes, and make the non-zero baseline clear so the chart does not mislead.
Software · AI-written, may contain errors
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