(a) Show this information in an ordered stem and leaf diagram.(3)
One of these students is going to be chosen at random.
(b) Find the probability that this student has a test mark less than 28 (2)
Mark scheme (a)
Answer
Mark
Notes
1
4 6 8 9
2
1 2 3 5 7 9
3
0 4 6 8 8
4
1 3 6 6 8
3
B2 for correct ordered stem and leaf (B1 for fully correct unordered, or ordered with one error or omission) B1 (indep) for key (units not required but must be correct if stated) eg. 1 | 4 = 14 (marks)
Mark scheme (b)
Answer
Mark
Notes
\(\dfrac{9}{20}\) oe
2
B2 for \(\dfrac{9}{20}\) oe or ft from stem and leaf diagram (B1 for \(\dfrac{x}{20}\) where \(x \lt 20\), \(x \neq 9\) or \(\dfrac{9}{y}\) where \(y \gt 9\) or ft from stem and leaf diagram)
