Foundation January 2019 Paper 2 Q16
16 The table shows information about the number of birds each of 40 people counted in their garden one morning.
| Number of birds | Frequency |
|---|---|
| 1 − 5 | 5 |
| 6 − 10 | 10 |
| 11 − 15 | 16 |
| 16 − 20 | 9 |
(a) Write down the modal class. (1)
(b) Work out an estimate for the mean number of birds. (4)
| Scheme | Marks |
|---|---|
| 11 – 15 | B1 |
| (1) |
| Scheme | Marks |
|---|---|
| 3 × 5 + 8 × 10 + 13 × 16 + 18 × 9 or 15 + 80 + 208 + 162 or 465 | M2 |
| (3 × 5 + 8 × 10 + 13 × 16 + 18 × 9) ÷ 40 or (15 + 80 + 208 + 162) ÷ 40 or 465 ÷ 40 | M1 |
| 11.625 | A1 |
| (4) | |
| (5 marks) |
Notes
M2: \(f \times n\) for at least 3 products with correct mid-interval values and intention to add
If not M2 then award M1 for
\(n\) used consistently for at least 3 products within interval and intention to add
or
at least 3 products with correct mid-interval values with no intention to add
M1: dep on M1
NB: accept their 40 if addition shown
A1: Accept 11.6 or 11.63 or 12 if correct working seen (465 ÷ 40 oe)