Question 1: What is the purpose of the key in a stem and leaf diagram?

Answer: To explain what the stems and leaves represent and how to interpret the diagram

Question 2: Create a key for the following stem and leaf diagram: Stems: 1, 2, 3 Leaves: 4, 5, 6, 7 Data: 14, 15, 16, 17, 24, 25, 26, 27, 34, 35, 36, 37.

Answer: Key: 1 | 4, 5, 6, 7; 2 | 4, 5, 6, 7; 3 | 4, 5, 6, 7

Question 3: Identify the mistake in this key: '5 | 0, 1, 2' representing data 50, 51, 52.

Answer: The stem '5' should represent 50–59, so leaves should be 0,1,2 for data 50, 51, 52. (Mistake: if leaves are not in this range, the key is incorrect)

Question 4: Explain why a clear key is important when creating a stem and leaf diagram.

Answer: It helps interpret the data accurately and ensures others understand the diagram correctly.

Question 5: Construct a key for the following data: 23, 24, 27, 29, 31, 33, 35, 37.

Answer: Key: 2 | 3, 4, 7, 9; 3 | 1, 3, 5, 7

Question 6: A stem and leaf diagram has stems 0, 1, 2, 3 and leaves 4, 5, 6, 7, 8, 9. The key reads '1 | 2' representing 12. What does this tell you about the data?

Answer: It indicates that 12 is part of the data set, with '1' as the tens digit and '2' as the units digit.

Question 7: Identify the error in this key: '4 | 0, 1, 2' for data 40, 41, 42.

Answer: The key correctly represents 40, 41, 42 if the stem is 4 and leaves are 0, 1, 2; no error.

Question 8: Describe how creating a key can help in comparing two different stem and leaf diagrams.

Answer: A clear key allows easy comparison of data ranges, frequencies, and helps interpret differences accurately.

Question 9: What common mistake might students make when creating a key for a data set with values between 10 and 99?

Answer: Incorrectly grouping the data, such as assigning wrong stems or leaves, or not clearly defining the ranges.

Question 10: Construct a challenging key for the data set: 56, 57, 61, 62, 65, 66, 70, 72, 75.

Answer: Key: 5 | 6, 7; 6 | 1, 2, 5, 6; 7 | 0, 2, 5