Robinson Tuition
Year 8 · Key Stage 3 · free KS3 maths worksheet

Scatter graphs and stem and leaf

12 original questions, 39 marks. Type your answers below for an instant mark and a score (algebra in any equivalent form, e.g. 2sqrt(3) or 2√3), or print the worksheet, mark it with the answers sheet, and use the solutions to see every step written out by hand.

Worksheet PDFWorked solutions PDFAnswers PDF

The questions

1

Write down the type of correlation you would expect to see in a scatter graph of each of the following.

  1. The daily temperature and the number of ice creams sold at a kiosk.
  2. The age of a car and its value.
2 marks
Show answer
a) positive correlation b) negative correlation
2

Here are three scatter graphs.

For each graph, write down the type of correlation it shows.

ABC
3 marks
Show answer
A) positive correlation B) negative correlation C) no correlation
3

The stem and leaf diagram shows the masses, in grams, of some tomatoes.

StemLeaves
21  4  6
30  2  5  8
43  7

Key: 2 | 1 = 21 grams

Find the range of the masses.

2 marks
Show answer
26 grams
4

The scatter graph shows the number of hours of sunshine and the number of visitors to a country park on each of 10 days.

  1. Describe the correlation shown by the scatter graph.
  2. On another day there were 7.5 hours of sunshine. By drawing a line of best fit, estimate the number of visitors to the park on this day.
0123456789101112020406080100120140160180200220240Hours of sunshineNumber of visitors
3 marks
Show answer
a) positive correlation b) approximately 160 (accept 150-175)
5

Here are the numbers of keepy-uppies done by 14 pupils in a PE lesson.

34  12  27  41  18  25  33  9  22  38  15  29  30  44

  1. Draw an ordered stem and leaf diagram for these numbers. Include a key.
  2. Work out the median.
  3. Work out the range.
StemLeaves
4 marks
Show answer
a) 0 | 9; 1 | 2 5 8; 2 | 2 5 7 9; 3 | 0 3 4 8; 4 | 1 4 with key 1 | 2 = 12 b) 28 c) 35
6

The stem and leaf diagram shows the number of press-ups 11 students did in one minute.

StemLeaves
06  8
11  3  5  7  9
22  4  6  8

Key: 1 | 1 = 11 press-ups

  1. Find the median number of press-ups.
  2. Find the range of the number of press-ups.
3 marks
Show answer
a) 17 b) 22
7

The table shows how long 8 pupils spend on their phones each day and how long they sleep each night.

Phone (hours)11.522.5344.55
Sleep (hours)9.59.298.68.47.87.67.2

The first six points are plotted on the scatter graph.

  1. Plot the last two points.
  2. Describe the correlation.
  3. Draw a line of best fit. Use it to estimate how long a pupil who spends 3.5 hours a day on their phone sleeps.
012345666.577.588.599.510Time on phone each day (hours)Sleep each night (hours)
4 marks
Show answer
a) (4.5, 7.6) and (5, 7.2) plotted b) negative correlation c) about 8.1 hours (accept 7.9 to 8.3)
8

The scatter graph shows the outside temperature, in °C, and the number of portions of soup sold by a cafe on each of 8 days.

  1. One of the points is an outlier. Write down the coordinates of this point.
  2. Ignoring the outlier, use the graph to estimate the number of portions of soup sold on a day when the outside temperature is 9 °C.
024681012141618200510152025303540455055606570Temperature (°C)Portions of soup sold
3 marks
Show answer
a) (11, 10) b) approximately 47 (accept 44-50)
9

The stem and leaf diagram shows the scores of 15 pupils in a times tables quiz.

StemLeaves
15  8  8
20  3  6  6  6  9
31  2  4  7
40  5

Key: 2 | 3 = 23

Work out

  1. the mode
  2. the median
  3. the mean
3 marks
Show answer
a) 26 b) 26 c) 28
10

11 pupils from Year 7 and 11 pupils from Year 8 each solved a puzzle. The back-to-back stem and leaf diagram shows their times, in seconds.

Year 7StemYear 8
8  5  211  3  4  6  9
7  4  4  120  2  5  6
8  3  031  5
14

Key: 2 | 1 | 3 means 12 seconds for Year 7 and 13 seconds for Year 8

  1. Work out the median and the range for each year group.
  2. Make two comparisons between the times of the two year groups.
4 marks
Show answer
a) Year 7 median 24, range 29; Year 8 median 20, range 24 b) Year 8 faster on average and more consistent
11

The stem and leaf diagram shows the times, in minutes, that 15 students in Class A took to finish a puzzle.

StemLeaves
21  4  8
30  2  3  5  7  9
42  4  6  8
50  3

Key: 2 | 1 = 21 minutes

For Class B, the median time was 38 minutes and the range of the times was 15 minutes.

  1. Find the median time for Class A.
  2. Find the range of the times for Class A.
  3. Compare the times of Class A with the times of Class B.
4 marks
Show answer
a) 37 minutes b) 32 minutes c) Class A slightly faster on average (lower median); Class B more consistent (smaller range)
12

The scatter graph shows the rainfall, in mm, and the number of umbrellas sold at a market stall on each of 8 days.

  1. Describe the correlation shown by the graph.
  2. One point is an outlier. Circle this point and write down its coordinates.
  3. Ignoring the outlier, estimate the number of umbrellas sold on a day with 7 mm of rainfall.
0123456789101112051015202530354045505560Rainfall (mm)Umbrellas sold
4 marks
Show answer
a) positive correlation b) (3, 45) c) approximately 35 (accept 32-38)

Your score

Answer the questions above and your score appears here.

Every question here is original and written by Robinson Tuition. It follows the Key Stage 3 programme of study; Year 9 sheets end with extension questions for top sets.

All Year 8 topics