NumericalModerate3 marks
The mean of the following data is 16. Calculate the value of f.
Topic: Mean / median / mode / quartiles
Previous-year question practice database
Answer
Exam answer
Values x: 5, 10, 15, 20, 25
Frequencies f: 3, 7, f, 9, 6
| x | f | fx |
|---|---|---|
| 5 | 3 | 15 |
| 10 | 7 | 70 |
| 15 | f | 15f |
| 20 | 9 | 180 |
| 25 | 6 | 150 |
Σf = 25 + f
Σfx = 415 + 15f
Given mean = 16
Formula:
Mean = Σfx/Σf
16 = (415 + 15f)/(25 + f)
400 + 16f = 415 + 15f
f = 15
Answer:
f = 15.
Explanation
Form the fx column, use mean = Σfx/Σf, and solve the resulting linear equation for the missing frequency.
More from Measure of Central Tendency (Mean, Median, Quartiles and Mode)
Rakhi’s mobile number has the following integers :
1, 6, 9, 8, 9, 1, 7, 8, 9
The mode of the above given data is :2026Find the mean of the following frequency distribution using step-deviation method.
Take assumed mean = 282026Assertion (A): The mean of first 9 natural numbers is 4.5.
Statement 2: Mean = Sum of all observations / Total number of observations2025mean, to the nearest whole number2025median2025the total number of workers.2025