RevisionDojo

Exercises for Question Type 4: Finding the value of the frequency of a specific class with some condition on mean, median or mode - IB | RevisionDojo

Question 1

The table shows grouped exam scores. Find the missing frequency $x$ if the mean score is $70$ (use class midpoints).

Score	Frequency
50–60	6
60–70	$x$
70–80	9
80–90	5

[3]

Question 2

The table shows grouped heights (cm). Find the missing frequency $x$ if the mean height is $40$ cm. Use class midpoints.

Height (cm)	Frequency
15–25	3
25–35	$x$
35–45	8
45–55	6
55–65	3

[4]

Question 3

The table shows grouped travel distances (km). Find the missing frequency $x$ if the median distance is $148$ km.

Distance (km)	Frequency
100–120	5
120–140	9
140–160	$x$
160–180	7
180–200	5

[5]

Question 4

The table shows grouped ages. Find the missing frequency $x$ if the median age is $33$ years.

Age ( $A$ ) years	Frequency
$10 \le A < 20$	5
$20 \le A < 30$	3
$30 \le A < 40$	$x$
$40 \le A < 50$	4

[3]

Question 5

The grouped frequency table shows weights ( $w$ kg). Find the missing frequency $x$ if the modal weight is $24$ kg.

Weight ( $w$ kg)	Frequency
$0 \le w < 10$	5
$10 \le w < 20$	7
$20 \le w < 30$	$x$
$30 \le w < 40$	6
$40 \le w < 50$	4

[4]

Question 6

The table shows grouped repair costs (USD). Find the missing frequency $x$ if the mode is $25$ .

Cost (USD)	Frequency
10–20	6
20–30	11
30–40	$x$
40–50	4

[5]

Question 7

The table shows grouped commute times (minutes). Find the missing frequency $x$ if the median commute time is $25$ minutes.

Time (min)	Frequency
0–10	$x$
10–20	$8$
20–30	$12$
30–40	$10$

[4]

Question 8

The table shows grouped weekly expenses. The mode of the expenses is $47$ . Find the missing frequency $x$ .

Expense ($)	Frequency
$30\text{--}40$	$8$
$40\text{--}50$	$x$
$50\text{--}60$	$12$
$60\text{--}70$	$6$

[3]

Question 9

The following grouped data shows times (in minutes). Find the missing frequency $x$ if the mean time is $24$ minutes. Use class midpoints.

Time (min)	Frequency
0–10	4
10–20	6
20–30	$x$
30–40	5
40–50	3

[5]

Question 10

The table shows a discrete distribution of incomes. Find the missing frequency $k$ if the mean income is $37$ .

Income	Frequency
$15$	$2$
$25$	$5$
$35$	$k$
$45$	$4$
$55$	$3$
$65$	$1$

[5]

Question 11

The table shows a discrete distribution of ratings. Find the missing frequency $x$ if the mean rating is $2.9$ .

Rating	Frequency
1	4
2	7
3	$x$
4	5
5	2

[3]

Question 12

The table shows a discrete distribution of scores. Find the missing frequency $x$ if the mean score is $59$ .

Score	Frequency
40	3
50	7
60	$x$
70	5
80	3

[3]

Question Type 4: Finding the value of the frequency of a specific class with some condition on mean, median or mode Exercises