A data set has values: 2, 4, 4, 5, 9. What is the mean and median?

• A. Mean = 4.8; Median = 4
• B. Mean = 4; Median = 4.5
• C. Mean = 4.5; Median = 4
• D. Mean = 5; Median = 4.5

Answer: (A)

When you summarize a set of numbers, the mean is the average you get by adding all values and dividing by how many values there are. Here, 2 + 4 + 4 + 5 + 9 = 24, and there are 5 numbers, so the mean is 24 ÷ 5 = 4.8.

The median is the middle number once the data are ordered from smallest to largest. The values in order are 2, 4, 4, 5, 9, and the middle one is the third value, which is 4. So the median is 4.

Therefore, the mean is 4.8 and the median is 4. The other options mix up these two values.