The stem-and-leaf plot below gives the test scores for the 21 students in Ms. Carter's science class. Use the plot to answer the questions that follow.

Question

Test score
6 | 1 6
7 | 0 3 3 5 6 8 9
8 | 1 1 3 4 5 5 8 8
9 | 0 2 6 7
Key: 6/1 means a score of 61.
(a) What was the lowest score overall?
(b) How many students scored in the 70s?
(c) What was the highest score in the 80s?

Answer 1

To interpret the stem-and-leaf plot:

• The stem represents the tens place, while the leaves represent the units place of the scores.

From the plot:

• Stem 6: The scores are 61, 66.
• Stem 7: The scores are 70, 73, 73, 75, 76, 78, 79.
• Stem 8: The scores are 81, 81, 83, 84, 85, 85, 88, 88.
• Stem 9: The scores are 90, 92, 96, 97.

Now to answer the questions:

(a) What was the lowest score overall?

• The lowest score is represented by the smallest number in the plot, which is 61.

(b) How many students scored in the 70s?

• The scores in the 70s are: 70, 73, 73, 75, 76, 78, 79.
• Counting these gives us a total of 7 students.

(c) What was the highest score in the 80s?

• The highest score in the 80s is represented by the highest number for the stem of 8, which is 88.

So the answers are: (a) 61
(b) 7
(c) 88