Handling Data and Statistics

What is the mean of these numbers: 2, 4, 6, 8?

• A5✓
• B6
• C6.5
• D8

Answer: Mean = (2 + 4 + 6 + 8) ÷ 4 = 20 ÷ 4 = 5.

What is the median of these numbers: 3, 5, 7, 9, 11?

• A5
• B7✓
• C9
• D11

Answer: The median is the middle value when in order. 3, 5, 7, 9, 11. The middle value is 7.

What is the mode of these numbers: 2, 3, 3, 5, 7, 3, 8?

• A2
• B3✓
• C5
• D8

Answer: The mode is the value that appears most often. 3 appears three times, so the mode is 3.

What is the range of these numbers: 2, 5, 8, 9, 15?

• A7
• B9
• C13✓
• D15

Answer: Range = highest value - lowest value = 15 - 2 = 13.

A data set has values: 10, 20, 30, 40, 50. What is the mean?

• A20
• B30✓
• C35
• D40

Answer: Mean = (10 + 20 + 30 + 40 + 50) ÷ 5 = 150 ÷ 5 = 30.

What is the median of: 1, 3, 5, 7?

• A3
• B4✓
• C5
• D6

Answer: With an even number of values, the median is the mean of the two middle values: (3 + 5) ÷ 2 = 4.

What is the range of: 100, 150, 200, 250, 300?

• A50
• B100
• C150
• D200✓

Answer: Range = 300 - 100 = 200.

A survey asks 20 people their age. The mean age is 35. What is the total of all ages?

• A35
• B55
• C700✓
• D7,000

Answer: Total = mean × number of values = 35 × 20 = 700.

What is the mode of: 5, 5, 5, 10, 10, 15?

• A5✓
• B10
• C15
• DNo mode

Answer: 5 appears three times, which is more than any other value, so the mode is 5.

The mean of 4 numbers is 10. The numbers are 8, 10, 12, and X. What is X?

• A8
• B10✓
• C12
• D14

Answer: Mean = (8 + 10 + 12 + X) ÷ 4 = 10. So (30 + X) = 40. X = 10.

A pie chart shows 25% of people prefer tea. If 100 people were surveyed, how many prefer tea?

• A10
• B20
• C25✓
• D50

Answer: 25% of 100 = 0.25 × 100 = 25 people.

What is the median of: 2, 4, 6, 8, 10?

• A4
• B6✓
• C8
• D10

Answer: The median is the middle value. 2, 4, 6, 8, 10. The middle value is 6.