Data Interpretation — Answer Key
Part A: Fix the Sentence
Each sentence has an error. Rewrite it correctly on the line.
1. Fix the sentence:
In a pictograph, each picture always means one item.
Corrected: In a pictograph, each picture means the number shown in the key.
The key tells you the value of one symbol so totals stay correct.
2. Fix the sentence:
On a stem-and-leaf plot, the stem is each single digit on the right.
Corrected: On a stem-and-leaf plot, the stem is the left digits and leaves are on the right.
Mixing stems and leaves changes every value you read off the plot.
3. Fix the sentence:
A tally mark group of four slashes with a cross means six items.
Corrected: A tally group of four slashes with a cross means five items.
Counting tallies as five-groups keeps frequency tables and totals accurate.
Part B: Fill in the Blank
Write the missing word or number on each line.
1. If a pictograph key shows one star equals 4 books, then 6 stars equals 24 books.
Each symbol stands for the key value, so totals come from multiplication.
2. On a stem-and-leaf plot, the entry stem 3 with leaf 7 represents the number 37.
Stems are tens and leaves are ones, joining to make a two-digit number.
3. A tally chart shows lll l (three plus one) for apples, meaning 4 apples were counted.
Adding individual marks gives the exact frequency for that category.
4. A frequency table lists 5, 7, 8, and 4 students; the total surveyed is 24 students.
Frequency totals show how many people or items were counted overall.
Part C: Short Answer
Answer each question in one or two complete sentences.
1. Explain how a tally chart can help you build a bar graph.
Sample answer: Each tally group becomes the height of one bar, so categories with more tallies get taller bars on the graph.
Tallies and bar heights both show frequency, making the conversion direct.
2. Why do pictographs need a key?
Sample answer: A key tells the value of each symbol so readers know if a picture stands for 1, 5, or more items when totaling.
Keys turn picture counts into accurate numerical totals for each row.