A manufacturer of light bulbs wishes to determine the life o

A manufacturer of light bulbs wishes to determine the life of a 100-watt bulb. What would his major problem be?

Solution

For determining the life of a 100 watt bulb if he wants to test the bulbs personally, then he has to wait for each bulb to have full life. This will take a lot of time

Instead he can take survey from a particular locality who use certain brands. The survey method is easy if sample is taken at random.
But the problems underlying are:

i) Either people are lazy or too busy to fill up the questionairre

ii) Even persons who fill up the questionairre do not take it seriously and tick any multiple choice which give incorrect data

iii) Collection of data from a vast number of households is cumbersome process

iv) Time may be wasted in preparing questions distributing and collecting back

v) Personal questions to people at random about bulb may be taking less time, but the persons may be knowing the life of the bulb. For example, if college students are selected they may not be aware of the exact time. Or some houses only housewives may know and others may not be aware.