Stage 8 - Q1 - 2 marks
For counts 0, 1, 2, 3 with frequencies 2, 5, 4, 1, find the total frequency.
Hint
Add the frequencies.
Stage 8 - Q2 - 2 marks
Find the median of 6, 8, 8, 10, 13.
Hint
The five values are already ordered.
Stage 8 - Q3 - 2 marks
A 120-degree sector in a pie chart of 90 people represents how many people?
Hint
Use the sector fraction of the total.
Stage 8 - Q4 - 2 marks
Daily values are 5, 7, 6, 10. Find the largest one-day increase.
Hint
Compare consecutive values.
Stage 8 - Q5 - 3 marks
Group A has values 5, 7, 9 and group B has values 6, 7, 8. Compare means and ranges.
Hint
Equal means can hide different consistency.
Stage 8 - Q6 - 4 marks
Ten values fall in \(0\le t<10\) and ten in \(10\le t<20\). Can the exact mean be found from these frequencies alone? Give a reason.
Hint
Think about moving observations within their classes.
Stage 8 - Q7 - 4 marks
A class records exact test scores 12, 14, 18, 18, 21, 25, 31, 34. Draw an ordered stem-and-leaf diagram and find the median.
Hint
Retain both eighteens before locating the middle pair.
Stage 8 - Q8 - 4 marks
Class A has 20 pupils and 60% cycle to school. Class B has 30 pupils and 50% cycle. Compare proportions and cyclist counts.
Hint
A higher percentage need not mean more people.
Stage 8 - Q9 - 5 marks
Two groups of sizes 4 and 6 have means 9 and 14. A report gives their combined mean as 11.5. Correct it and explain the error.
Hint
Use the number of observations behind each mean.
Stage 8 - Q10 - 6 marks
Two classes’ scores are A=(8, 9, 10, 10, 11, 12) and B=(5, 7, 10, 10, 13, 15). Choose a display that preserves individual scores. Compare means, medians and ranges, then evaluate: “A has a higher typical score and its teaching caused the difference.”
Hint
Separate centre, spread and causal explanation into three claims.