Hint
Use the stated units and precision. Count observations rather than the number of value rows.
Worked solution
(a)
Count observations rather than the number of value rows.
Adding frequencies gives 13.
Answer: \(13\)
(b)
Multiply each value by its frequency before summing.
The weighted total Σfx is 62.
Answer: \(62\)
(c)
Use Σfx/Σf.
Divide weighted total 62 by count 13, giving \(\displaystyle \frac{62}{13}\).
Answer: \(\displaystyle \frac{62}{13}\)
Maths4U indicative marking guidance
Maths4U indicative marking guidance, not an official mark scheme. Credit complete valid alternative methods and consequential reasoning. An unexplained result does not earn a method mark.
(a) · 2 marks
- 1 mark: Count observations rather than the number of value rows.
- 1 mark: Give the correct requested result, retaining signs, units and any domain restrictions.
Alternative methods: Any complete mathematically valid alternative method with the same restrictions and equivalent exact result is acceptable.
Common error: Keep intermediate values exact until the final step.
(b) · 2 marks
- 1 mark: Multiply each value by its frequency before summing.
- 1 mark: Give the correct requested result, retaining signs, units and any domain restrictions.
Alternative methods: Any complete mathematically valid alternative method with the same restrictions and equivalent exact result is acceptable.
Common error: Check the answer against the original conditions.
(c) · 2 marks
- 1 mark: Use Σfx/Σf.
- 1 mark: Give the correct requested result, retaining signs, units and any domain restrictions.
Alternative methods: Any complete mathematically valid alternative method with the same restrictions and equivalent exact result is acceptable.
Common error: Keep intermediate values exact until the final step.
Total: 6 marks.