BUILD FLUENCY. EARN YOUR ASCENT.Sign in Year 11
Unknown frequencies, grouped estimates and weighted spread
Free examples and worked answers. No account needed.
Practise the method.
Unknown frequencies, grouped estimates and weighted spread
Optional extension: Unknown frequencies, grouped estimates and weighted spread
Example 1
The frequency table has mean 211. Find the missing frequency x.
Show worked answer
Answer: 5
- totalfrequency:13+x18+5x+56=211.Usemean=totalvalue
- Solve for x=5.
Example 2
Estimate the mean using each class midpoint. Give an exact fraction if needed.
Show worked answer
Answer: 11184
- Use midpoints 8,16,24.
- The weighted total is 184, and total frequency is 11;
- estimated mean =11184.
Example 3
The frequency table has mean 16137. Find the missing frequency x.
Show worked answer
Answer: 3
- totalfrequency:13+x36+8x+77=16137.Usemean=totalvalue
- Solve for x=3.
Put it into practice.
Sign in to choose a set, get feedback and keep your progress.