Central angle from a percentage
\(\text{angle}=\frac{\text{percent}}{100}\times 360^\circ\)
Tahat Just Math · Self-paced practice
Read, Build and Summarize Data
Turn raw numbers into graphs and averages, one objective at a time.
- Construct and interpret circle graphs and central angles.
- Read line graphs and bar graphs.
- Build frequency distributions and histograms.
- Find the mean, median and mode, including from grouped data.
248 questions · 11 learning objectives
Objectives 1–3
Construct, calculate and interpret circle graphs
A circle graph (pie chart) shows how a whole is shared among categories. The full circle is \(360^\circ\), so each category receives a central angle proportional to its share of the total.
Central angle from a count
\(\text{angle}=\frac{\text{category count}}{\text{total count}}\times 360^\circ\)
Objectives 4–5
Read line graphs and bar graphs
Line graph
Shows how a quantity changes. Find the given value on the horizontal axis, move up to the line, then across to the vertical axis (or the reverse for the opposite question).
Bar graph
Compares categories. Read each bar's height on the scale, then add, subtract or compare as the question asks.
Objectives 6–7
Build frequency distributions and histograms
- Choose equal-width class intervals that cover the smallest to the largest value.
- Tally each data value into exactly one interval and count the frequency \(f\).
- Check that the frequencies add up to the number of data values.
- For a histogram, draw one bar per interval, with the bar height equal to its frequency and no gaps between bars.
Objectives 8–11
Mean, median and mode
Mean
\(\bar{x}=\frac{\sum x}{n}\)
Add all values and divide by the number of values.
Median
Order the data. The median is the middle value; for an even count, it is the mean of the two middle values.
Mode
The most frequent value. A data set can have one mode, several modes, or none.
Mean of a frequency distribution
\(\bar{x}=\frac{\sum xf}{\sum f}\)
Use the midpoint \(x\) of each interval, multiply by its frequency \(f\), then add the products and divide by the total frequency.
Chapter 15 · Mock exam
A focused 20-question test
Questions are selected at random from the objectives you choose, with at least one question from each selected objective. Answer in any order, flag questions to revisit, and review everything before you submit. Your score and answer review appear at the end. Use your school-approved tablet; phones should remain put away under classroom rules.
- 20random questions
- 40 minutesauto-submits when time ends
- Tab & focus monitoringends after 3 departures
Switching tabs or focusing another window is counted. Some split-screen modes keep both pages focused and visible, which a website cannot detect. This is not secure proctoring.
The test requests fullscreen when you start. Exiting fullscreen is recorded and pauses the test until you return to fullscreen. If fullscreen is unavailable, you can choose to continue without it.
Focused practice
Choose a learning objective
Practice one skill at a time, or use the full assessment from the hero section to review the entire chapter.
Random practice
Mixed practice across every objective
Chapter 15 contains 248 questions across 11 learning objectives. A random set always includes at least one question from every objective, so a set of 10 questions covers the whole chapter.