- IB
- Question Type 4: Finding the value of the frequency of a specific class with some condition on mean, median or mode
The frequency table below shows the distribution of a continuous variable .
Find the possible integer values of such that the mode lies in the class .
[4]The following table shows the grouped frequency distribution for a set of data.
| Class | Frequency |
|---|---|
| 10–19 | 4 |
| 20–29 | |
| 30–39 | 6 |
| 40–49 | 5 |
| 50–59 | 2 |
Find the value of , given that the mean of the distribution is 33.5.
[7]Find the smallest integer value of such that the mode of the following grouped data is in the class 20–29.
[3]The question asks for the unknown frequency in a grouped frequency distribution given the median of the distribution. Linear interpolation is used to solve for .
In the distribution below, find the value of such that the median of the distribution is 28.
| Class | Frequency |
|---|---|
| 10–19 | 4 |
| 20–29 | |
| 30–39 | 6 |
| 40–49 | 4 |
The following question tests the ability to calculate a missing frequency from a grouped frequency distribution given the mean.
A grouped frequency distribution is shown in the table below. Given that the mean of the distribution is , find the value of .
| Class | Frequency |
|---|---|
Calculate the frequency so that the mean of the data values in the following table is 65.
| Value | 50 | 60 | 80 |
|---|---|---|---|
| Frequency | 2 | 3 |
The following table shows the frequency distribution for a set of discrete data, where represents the frequency of the class 16–20.
Find the minimum integer value of such that the modal class of this distribution is 16–20.
| Class | Frequency |
|---|---|
| 1–5 | 3 |
| 6–10 | 5 |
| 11–15 | 7 |
| 16–20 | |
| 21–25 | 6 |
Determine the value of such that the median of the following frequency distribution is 45.
| Class | Frequency |
|---|---|
| 10–29 | 8 |
| 30–49 | |
| 50–69 | 6 |
| 70–89 | 4 |
Given the grouped data below, find the minimum integer value of such that the modal class is .
[3]
A frequency distribution has classes 0–9, 10–19, 20–29, 30–39, 40–49 with frequencies , , , , . Find so that the mean of the distribution is .
[7]The following table shows a frequency distribution.
| Class | Frequency |
|---|---|
Find the minimum integer value of such that the modal class is .
[3]Questions involving finding an unknown frequency from a given mean for ungrouped discrete data.
The following ungrouped data have frequencies , , , and values , , , . Find so that the mean is .
[3]