Answer the following
1. There are 32 students in Mr Tesla’s class.
20 are boys and 12 are girls.
The mean height of the boys is 151 cm.
The mean height of the girls is 148 cm.
Calculate the mean height of all the students in Mr Tesla’s class.
2. The table shows information about the numbers of certificates awarded in John’s
class
during a term.
Number of
Number of students
certificates
0
4
1
9
2
7
3
1
4
6
5
3
(a) Work out the median number of certificates awarded.
3. Emy asked 40 people how many text messages they each sent on Monday.
The table shows her results.
Number of text messages
Frequency
sent
0 to 4
6
5 to 9
3
10 to 14
5
15 to 19
12
20 to 24
14
(a) Write down the modal class.
(b) Calculate an estimate for the mean number of text messages sent
(c) What percentage of these 40 people sent 20 or more text messages?
4. Students in class 9D took part in a sponsored swim.
The table gives information about the amount of money, in £, raised by each
student.
Money raised (£x) Frequency
0 ≤x <6
4
6 ≤ x<12
6
12 ≤ x< 18
8
18 ≤ x< 24
9
24 ≤ x <30
3
Work out an estimate for the total amount of money raised by the students in class 9D