6 The table shows some information about the ages of 60 teachers.
Age (\(a\) years)
Frequency
\(20 \lt a \leqslant 30\)
6
\(30 \lt a \leqslant 40\)
16
\(40 \lt a \leqslant 50\)
14
\(50 \lt a \leqslant 60\)
22
\(60 \lt a \leqslant 70\)
2
(a) Write down the modal class interval. (1)
(b) Draw a frequency polygon for the information in the table.(2)
Mark scheme (a)
Answer
Mark
Notes
\(50 \lt a \leqslant 60\)
1
B1 for correctly identifying the modal class interval e.g. 50 – 60 oe
Mark scheme (b)
Answer
Mark
Notes
Polygon
2
B2 for fully correct frequency polygon - points plotted at the midpoint (B1 for all points plotted accurately but not joined with straight line segments or all points plotted accurately and joined with last joined to first to make a polygon or all points at the correct heights and consistently within or at the ends of the intervals and joined (can include joining last to first to make a polygon)) NB: ignore parts of graph drawn to the left of the 1st point or the right of the last point; ignore any histograms drawn.
