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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.
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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.
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