Hint
A frequency is a count of repeated observations. Identify the value attached to the greatest count.
Worked solution
(a)
\(\text{mode}=9\) because it has frequency 35.
Answer: \(9\).
Answer: \(9\)
(b)
\(\displaystyle \sum \frac{fx}{\sum}f= \frac{651}{83}\)
Answer: \(\displaystyle \frac{651}{83}\).
Answer: \(\displaystyle \frac{651}{83}\)
(c)
\(\sum f=83\)
Answer: \(83\).
Answer: \(83\)
Maths4U indicative marking guidance
Maths4U indicative marking guidance, not an official mark scheme. Credit valid alternative reasoning and consequential working; do not award a reasoning mark for an unexplained final answer.
(a) · 2 marks
- 1 mark: Identify the value attached to the greatest count.
- 1 mark: Obtain the stated result with the required sign, units and domain.
Alternative methods: Any complete mathematically valid method with the stated assumptions and equivalent result is acceptable.
Common error: Do not confuse the modal value with its frequency.
(b) · 2 marks
- 1 mark: Weight each distinct value by its frequency.
- 1 mark: Obtain the stated result with the required sign, units and domain.
Alternative methods: Any complete mathematically valid method with the stated assumptions and equivalent result is acceptable.
Common error: The mean of the distinct labels is not the mean of the observations.
(c) · 2 marks
- 1 mark: Add frequencies rather than counting table rows.
- 1 mark: Obtain the stated result with the required sign, units and domain.
Alternative methods: Any complete mathematically valid method with the stated assumptions and equivalent result is acceptable.
Common error: Do not confuse the modal value with its frequency.
Total: 6 marks.