What to do
A histogram displays how often data values fall into intervals, called bins or classes. For each bin, the bar’s height shows the frequency in that interval.
Step-by-step method
- Read the data carefully. Identify the smallest and largest values.
- Use the given bins. If intervals are already provided, keep their boundaries exactly as shown.
- Count values in each bin. Place every data value into the correct interval. Be consistent about whether endpoints belong to the left or right bin.
- Record the frequency. The height of each bar is the number of values in that bin.
- Draw the bars. On the horizontal axis, label the intervals. On the vertical axis, mark the frequency scale.
- Check your work. Add all frequencies. The total should match the number of data values.
Common mistakes to avoid
- Leaving out values that lie on bin boundaries.
- Mixing up histogram bars with bar chart categories.
- Using unequal widths if equal-width bins are expected.
Final check
Make sure every value is counted once, the axes are labeled, and the bar heights match the frequencies exactly. If the answer must be simplified, present the counts clearly and in the form requested.