Before choosing a graph, find out what was measured, who was included and what question the data can answer.
Distinguish categorical and numerical data, identify a dataset’s context, and separate observations from claims.
Data is information collected to answer a question. A count of favourite lunch choices answers a different question from the number of lunches sold. Before graphing, identify the people or objects studied, the variable recorded, the units and the time period. A graph without this context can be easy to read and still impossible to interpret fairly.
Categorical data sorts observations into groups, such as lunch choice or travel method. Numerical data records amounts. A count, such as the number of students, takes whole-number values; a measurement, such as travel time, can include decimal values. A numerical code on a jersey is a label, not a measurement: averaging jersey numbers does not describe player performance.
A sample is the group actually studied; a population is the larger group a claim concerns. If 18 of 30 students in one class prefer a later start, the sample proportion is 60%. It does not establish that 60% of all students agree. Ask how the class was chosen, who did not respond and whether the question encouraged a particular answer.
An observation describes the recorded evidence. An inference proposes an explanation. A chart showing more bike trips in May than April supports a statement about those recorded trips. It does not, by itself, prove that a new bike rack caused the increase. Weather, attendance or counting methods might also have changed.
Enter one label and value per line, separated by a comma. This tool supports 2–12 non-negative values. The table and graph always use the same data.
Line graphs use equally spaced positions here: use observations at equal time intervals. Do not use a line to connect unrelated categories. Circle graphs require a positive total.
Think about whether adding two route numbers has a meaningful interpretation.
The route number is a category label. Count students in each route category; do not average the route numbers.
Find the denominator and the way respondents were selected.
Ask how many people responded, who was invited, when the survey occurred and how the question was worded. Eight out of ten customers and 800 randomly selected students are different evidence.
Feedback explains your chosen response. These activities are practice, not a school mark.
Find a percentage in an advertisement. Identify the numerator, denominator, group and date. Write a version of the claim that stays within the available evidence.
Design two sampling methods for the same school question. Explain which is more likely to include students with different experiences. This sampling work supports graph critique; formal survey-project design extends beyond the central SP1 outcome.