In which of the following studies is it necessary to study a sample instead of the whole population?
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Finding the mean burning life of the electric bulbs made by a factory, where each bulb tested is used up
To find the burning life of a bulb, the bulb has to be kept on until it fuses, so a tested bulb can no longer be sold. If every bulb were tested, nothing would be left to sell. So only a sample of bulbs can be tested, and the result is used to draw a conclusion about all the bulbs.
In the other studies the population is small (40 students, 25 employees, 30 families), and every member can easily be studied.