Standard deviation Quiz

1. A data set has a standard deviation of $0$. What does this mean?

• A. All the values are $0$
• B. The mean is $0$
• C. All the values are equal
• D. The data has no mean

2. Two classes both have a mean mark of $60$. Class A has $\sigma=5$ and Class B has $\sigma=12$. Which statement is correct?

• A. Class A's marks are less spread out
• B. Class B's marks are less spread out
• C. Class A has the higher mean
• D. Class B has the higher mean

3. A frequency table shows $x=1,2,3,4$ with frequencies $1,3,4,2$. What is the mean?

• A. $2.5$
• B. $2.0$
• C. $27$
• D. $2.7$

4. A list has mean $12$ and standard deviation $3.2$. A new value of $12$ is added. What happens?

• A. The mean and the standard deviation both increase
• B. The mean stays $12$ and the standard deviation decreases
• C. The mean stays $12$ and the standard deviation stays $3.2$
• D. The mean decreases and the standard deviation increases

5. Which would a quality manager use to say that a factory's machine is more consistent than another's?

• A. A higher mean
• B. A larger range of values
• C. A smaller standard deviation
• D. A larger number of items