Page 191 - MAT KS3 Y8 Cambridge CheckPoint

18.5 Drawing conclusions

✦ Exercise 18.5

1 Mr Lopez makes pottery vases. He sells them on the internet. Key: 24 20 means $24.20
The stem-and-leaf diagram shows the prices of the vases he 24 20 33 79 80 90
sells in one week. 25 05 25 50 70 70 99 99
Mr Lopez makes a profit if the mean price is greater 26 40 45 60 65 90
than $25.50.
Does Mr Lopez make a profit this week?
Show your working.

2 The bar-line graphs show the number of goals scored by two hockey teams in 25 matches.
Tanesha thinks that Allerton score more goals on average than Batesfield.
a Explain how Tanesha could be right.
b Explain how Tanesha could be wrong.

Number of goals scored by Allerton Number of goals scored by Batesfield
10 8 15
Number of matches 6 4 Number of matches 10 5

0 2 0
0 1 2 3 4 0 1 2 3 4
Number of goals scored Number of goals scored

3 The students in class 8P ran the school cross-country (long-distance running) course in
their PE lesson.
The frequency diagram shows the time taken by the students in class 8P to complete the course.
The PE teacher says: ‘If 60% of you finish the course in less than 15 minutes, you can all go early for
lunch.’
Do class 8P go early for lunch?
Show your working.

16 Time taken to complete course

12
Frequency 8

4

0 5 10 15 20 25 30
Time (minutes)

18 Interpreting and discussing results 189