Question

. Describe the difference between a "population" and a "sample." What is a "representative sample"? What is the best way to achieve representativeness in a sample?

Answer 1

• population is defined as total group of individuals of a defined group that we are studying or collecting information for data driven desicions.
• eg:mean height of men,it includes all men that have lived,are alive,and will live in future.
• it is impossible to survey such an entire population as not all the members are observable.
• it is costly
• it is time consuming.

sample is a part of population selected as a group of people who take part in the investigation.

• eg: measuring mean height of a sample of people selected from the population
• it is cost effective
• doesnt consume much time
• disadvantage:since fewer members are under study ,it leads to loss of some information.

representative sample is a small quantity of something that accurately reflects the larger entity.eg:in a class room of 30 students,half the students are males and half the students are females,a representative sample would include six students:3 males and 3 females.

any sampling method that uses random selection or random sampling or probability sample technique is the best way to achieve representativeness in a sample.. hence probability sampling is the best way.