How do you create a histogram from a frequency table?
Let's use a set of actual data representing the marks received by the students participating in the last edition of the Bucharest English Language Contest.
We'll work our way from the raw data to the histogram, passing through the frequency table in the process. We had 313 students participating in the contest. They received marks ranging from 65 to 100, on a 0-100 scale. I'll put the data in a Google sheet document .
Step 1: Get the raw data in tabular format (see the sheet 1 - "Raw data" - in the Google sheet here ).
Step 2: Get the ordered data in tabular format (see the sheet 2 - "Ordered data~ - in the Google sheet here ).
Step 3: Notice that the marks values range from 65 to 100. This gives us a range of 36. A convenient way to split this range into equal intervals is getting 6 intervals with an interval step of 6, as follows:
- Interval 1 : from 65 to 70
- Interval 2 : from 71 to 76
- Interval 3 : from 77 to 82
- Interval 4 : from 83 to 88
- Interval 5 : from 89 to 94
- Interval 6: from 95 to 100
Step 4: Get the frequency table for the intervals defined at step 3 (see the sheet 3 "Frequency table" - in the Google sheet here ).
- Frequency 1 (no of students getting marks 65-70): 3
- Frequency 2 (no of students getting marks 71-76): 5
- Frequency 3 (no of students getting marks 77-82): 24
- Frequency 4 (no of students getting marks 83-88): 72
- Frequency 5 (no of students getting marks 89-94): 114
- Frequency 6 (no of students getting marks 95-100): 98
Step 5: From the frequency table created at step 4, get the histogram by using a column chart type. Marks will be represented on the X-axis and frequencies on the Y-axis: