AS1 - Data collection

Question 1

Define population:

Answer 1

the whole set of items that are of interest

Question 2

What are 2 ways of collecting data from a population?

Answer 2

-census
-sample

Question 3

Define census:

Answer 3

a method of collecting data from a population that involves observing/measuring every member of a population

Question 4

Give some pros and cons of using a census:

Answer 4

-fully accurate/representative

-time consuming and expensive
-hard to process data for larger populations
-can’t be used when the testing process destroys the item

Question 5

Define a sample:

Answer 5

a selection of observations taken from a subset of the population which is used to find out information about the population as a whole

Question 6

Give some pros and cons of using a sample:

Answer 6

-far less time consuming/expensive than a census
-less data to process

-might not be accurate as the sample may not be large enough to give info about the minorities in a population

Question 7

What is a sampling frame?

Answer 7

a numbered list of sampling units from a population

Question 8

Name 3 methods of random and 2 non-random sampling:

Answer 8

-simple random
-systematic
-stratified

-quota
-oppurtunity/convenience

Question 9

Define simple random sampling:

Answer 9

a sample of size n where every sampling unit in a population has an equal chance of being selected

Question 10

Describe systematic sampling:

Answer 10

the required elements are chosen at regular intervals from an ordered list, after a random starting point has been chosen

Question 11

Describe stratified sampling:

Answer 11

the population is split up into mutually exclusive strata, and the proportion of each strata in the sample will reflect the proportion of each strata in the population

Question 12

Describe quota sampling:

Answer 12

-the population is divided up into groups according to certain characteristics, and a quota (number of people we want) for that group is set

-people are selected using opportunity sampling until the quota of each group has been met

Question 13

Give some pros and cons of quota sampling:

Answer 13

-allows a small sample to still be representative of the population
-no sampling frame needed so it is quicker/cheaper

-non-random sampling can introduce bias
-need to divide population into groups which could be costly/inaccurate

Question 14

Describe opportunity sampling:

Answer 14

taking a sample from the things that are most easily available to a researcher at a particular time

Question 15

Give some pros and cons of opportunity sampling:

Answer 15

-quick/easy/inexpensive to carry out

-unlikely to provide a representative sample
-highly dependent on the individual researcher