Quartiles, deciles and percentiles

STA 111. Practice questions, not past papers.

Lessons

• Ranks and interpolation
• Grouped quantiles and spread

Practice questions

1. The 7th decile equals which percentile?

   Statistics study edition practice item Q052; Source: T25-28

2. The semi-interquartile range is what?

   Statistics study edition practice item Q053; Source: T25-28

3. In the stated ungrouped interpolation rule, which position is used for probability p?

   Statistics study edition practice item Q054; Source: T25-28

4. Which count replaces N/2 when finding a general grouped percentile p?

   Statistics study edition practice item Q055; Source: T25-28

5. Use rank (n+1)p for sorted data 2,4,6,8,10,12,14. Find percentile p=0.25. Give the value to 4 decimal places.

   Statistics study edition practice item Q056; Source: T25-27

6. Use rank (n+1)p for sorted data 2,4,6,8,10,12,14. Find percentile p=0.75. Give the value to 4 decimal places.

   Statistics study edition practice item Q057; Source: T25-27

7. Q1=1.055 and Q3=1.230 on the source numerical scale. Find the IQR. Give the value to 4 decimal places.

   Statistics study edition practice item Q058; Source: T26-27

8. For grouped data, p=0.25, N=45, L=39.5, C=7, f=8, h=10. Estimate Q1. Give the value to 4 decimal places.

   Statistics study edition practice item Q059; Source: T12, T25-28

9. The 50th percentile is the _____.

   Statistics study edition practice item F020; Source: T25-28

10. The third quartile is the _____ percentile.

    Statistics study edition practice item F021; Source: T25-28

Topic gap report