Data selection: contiguous, non-contiguous or a specified range
Contiguous data is one unbroken block of adjacent cells. Non-contiguous data is two or more separate ranges selected together, so a chart can use cells that do not touch. A specified data range is the exact set of rows/columns the task names. The task wording decides which rows are IN the chart and which -- a "Total" row, or a text-only heading -- must be left OUT; re-read it before charting to avoid an under- or over-selected range.
Labelling: an axis title is not its axis labels
A fully labelled chart names every element the task lists. Chart title = what the chart shows; legend = the key matching each colour or pattern to its series/category. An axis title is one heading for the whole axis (e.g. "Region"); its axis labels are the individual tick text or scale values along it -- treating the two as the same is a common labelling error. A pie sector label adds the group name and its value or percentage share.
Second series, second axis and value formatting
A second data series adds a further set of values to one chart (e.g. two years of sales). A second axis gives that series its own value scale -- needed when the two series use very different units or ranges, since one shared scale would squash the smaller series flat. Separately, values can be formatted to a set number of decimal places or to display a currency symbol; these are display instructions, independent of data selection or chart type.
Drawn from real examiner reports.
Charting a "Total" row in a pie
A source table often has a "Total" row that sums the genuine categories, beside the rows that ARE the chart data. Selecting it into a pie chart's range adds an extra sector as large as all the real sectors combined and shrinks every real sector's percentage. Fix: scan for a Total row or column and deliberately exclude it, while still selecting every genuine category.
s23 P21 Q26-28: candidates who included a "Total" row produced a pie with an extra sector and distorted percentages.
Sector label missing its name or %
A fully specified pie sector label shows BOTH the group name AND its percentage -- not one alone -- to the exact decimal places asked (commonly 1 dp) and placed where the task says (usually outside the sector). Showing only a percentage, only a name, the wrong number of decimal places, or a label inside the sector loses the mark even when the chart data itself is correct.
s23 P21 Q26-28: sector labels needed the group name and the percentage to 1 dp, placed outside each sector; an incomplete label lost marks even where the chart was otherwise correct.
Axis title typed on the wrong axis
The category axis title (heading for the axis holding the group names) and the value axis title (heading for the numeric scale) are easily swapped, especially after a chart is switched between vertical and horizontal -- the "bottom" axis is not always the category axis. Check which axis actually holds the category names before typing a title into it.
w23 P02 Q8-12: the category axis title had to sit on the axis holding the region names, not on the value axis.
Axis "title" confused with axis "labels"
An axis title is the single heading for the whole axis (e.g. "Sales"); the axis labels are the tick entries along it -- the category names, or the scale numbers 0, 300, 600... Treating the two as the same, or adding one when the task asked for the other, is marked as incomplete labelling. Add the title AND the labels the task lists, ticking each off separately.
Leaving the axis scale at its default
When a task gives an exact value-axis scale (e.g. minimum 0, maximum 1500, increments 300), the software's automatic default -- chosen from the data -- usually will not match it, so a default-scaled chart fails the requirement. Open the axis properties and set the minimum, maximum and increment explicitly to the values given, never leaving the automatic scale in place.
w23 P02 Q8-12: the value-axis scale had to be set exactly (min 0, max 1500, increments 300), not left at the software default.
Wrong chart type for the data shape
The chart type must fit the data: a pie chart shows each category's share of one whole; a bar/column chart compares separate discrete categories; a line chart shows how a value changes across a sequence such as time. Choosing a pie for data that compares discrete categories, or a line for data with no time/sequence order, misrepresents it even when drawn neatly.
Read data selection for include AND exclude
Before charting, re-read which rows/columns are IN the chart and which are deliberately OUT -- a "Total" row or a text-only heading -- and decide whether the selection is contiguous, non-contiguous or a named range. Mis-reading it builds a correct-looking chart on the wrong data.
Set scale and formatting explicitly
Never accept the software's automatic scale or number format when a task specifies them. Set the axis minimum, maximum and increment exactly as given, and apply the stated decimal places or currency symbol -- a chart that looks right still loses marks for a default scale.
Work the syllabus order as a checklist
Chart tasks bundle several requirements in one instruction. Work them in a fixed order -- select data, choose type, add every named label, add any second series/axis, format values, set the axis scale, enhance last -- ticking off each named element, not a software default.
Full notes, flashcards, Q&A and the topic quiz for every premium subject.
Premium plans are US$8.99/month or US$49.99/year — first month free.
Studying with a parent's blessing? Show them this.
