From measurements across a shaft, the values 4, 5, 6, 9, 9, and 9 mm were recorded. What is the mean?

From measurements across a shaft, the values 4, 5, 6, 9, 9, and 9 mm were recorded. What is the mean?

• A. 7 mm
• B. 4 mm
• C. 9 mm
• D. 5 mm

Answer: (A)

Calculating the average (mean) of a set of measurements means adding all the values together and then dividing by how many measurements you have. Add them up: 4 + 5 + 6 + 9 + 9 + 9 = 42. There are 6 measurements, so the mean = 42 ÷ 6 = 7 mm. So the mean is 7 mm. This value represents the balance point of the data, sitting between the lower group (4–6 mm) and the higher group (9 mm).

Calculating the average (mean) of a set of measurements means adding all the values together and then dividing by how many measurements you have.

Add them up: 4 + 5 + 6 + 9 + 9 + 9 = 42.

There are 6 measurements, so the mean = 42 ÷ 6 = 7 mm.

So the mean is 7 mm. This value represents the balance point of the data, sitting between the lower group (4–6 mm) and the higher group (9 mm).