Measures of location and spread Quiz

1. For 5 values, $\sum x=30$ and $\sum x^2=200$. What is the standard deviation, using $\sqrt{S_{xx}/n}$?

• A. 2
• B. 4
• C. 6
• D. 40

2. $y=\frac{x-10}{2}$ and $\bar y=6$. What is $\bar x$?

• A. 8
• B. 16
• C. 22
• D. 12

3. For grouped data with $n=80$, which position is used to estimate the lower quartile?

• A. 10th
• B. 20th
• C. 40th
• D. 60th

4. Which measure of spread is least affected by an extreme value?

• A. Range
• B. Standard deviation
• C. Variance
• D. Interquartile range

5. The values 1, 2 and 3 have frequencies 2, 3 and 5. What is the mean?

• A. 2.3
• B. 2
• C. 2.5
• D. 3