Dispersion, variance and relative variation

STA 111. Practice questions, not past papers.

Lessons

• Range, absolute deviations and variance
• Frequency formulas and coefficient of variation

Practice questions

1. Which divisor is used for the usual unbiased sample variance?

   Statistics study edition practice item Q060; Source: T28-34

2. Variance is expressed in what units?

   Statistics study edition practice item Q061; Source: T28-34

3. The coefficient of variation is commonly computed as what?

   Statistics study edition practice item Q062; Source: T28-34

4. Adding a constant to all observations changes variance how?

   Statistics study edition practice item Q063; Source: T28-34

5. Treat 3, 5, 7, 9, 11 as the entire population. Find its variance. Give the value to 4 decimal places.

   Statistics study edition practice item Q064; Source: T29-32

6. Treat 2, 4, 6 as the entire population. Find its variance. Give the value to 4 decimal places.

   Statistics study edition practice item Q065; Source: T29-32

7. Treat 1, 2, 3, 4 as the entire population. Find its variance. Give the value to 4 decimal places.

   Statistics study edition practice item Q066; Source: T29-32

8. For a positive ratio-scale variable, mean=20 and SD=5. Find CV in percent. Give the value to 4 decimal places.

   Statistics study edition practice item Q067; Source: T34

9. For a positive ratio-scale variable, mean=60 and SD=12. Find CV in percent. Give the value to 4 decimal places.

   Statistics study edition practice item Q068; Source: T34

10. For a positive ratio-scale variable, mean=15 and SD=3. Find CV in percent. Give the value to 4 decimal places.

    Statistics study edition practice item Q069; Source: T34

Topic gap report