Sampling

Question 1

What is a census?

Answer 1

An investigation of all the individual elements that make up a population

Question 2

Why is sampling often more benefical than a census?

Answer 2

• Cost & time
• Accurate and reliable results
• Destruction of test units

Question 3

What is random sampling error?

Answer 3

• The difference between a sample result of a census conducted using identical procedures
• Statistical fluctuation due to chance variations in elements selected for a sample

Question 4

What is a systematic (non-sampling) error?

Answer 4

• Error resulting from some imperfect aspect of the research design, such as mistakes in sample selection, sampling frame error or non-response.

Question 5

Key things to note about random sampling error?

Answer 5

• As sample sizes increase, random sampling decreases
• The more people we ask, the more likely the same result is going to reflect the true result

Question 6

What is probability sampling?

Answer 6

• Sampling tehcnique in which every member of the population has a known, non-zero probability of selection

Question 7

What is non-probability sampling?

Answer 7

A sampling technique in which units of the sample are selected on the basis of personal judgement or convenience. The probability of any particular member of the population being chosen is unknown.

Question 8

What is simple random sampling?

Answer 8

• A sampling procedure that assures each element in the population an equal chance of being included in the sample.

Question 9

What is systematic sampling?

Answer 9

• A procedure in which a starting point is selected by a random process and then ever nth number on the list is selected

Question 10

What is stratified sampling?

Answer 10

Subsamples that are more or less equal on some characteristic are drawn from within each stratum of the population

Question 11

What is cluster sampling?

Answer 11

• An economically efficient sampling technique in which the primary sampling unit is not the individual element in the population but a large cluster of elements

Question 12

What is convenience sampling?

Answer 12

• procedure of obtaining people or units that are most convienetly available

Question 13

What is judgement sampling?

Answer 13

Experienced individual selects the sample based on personal judgement about some appropriate characteristic of sample member.

Question 14

What is quota sampling?

Answer 14

• Various subgroups of a population will be represented on pertinent characteristics to the exact extenet that the investigator desires

Question 15

What is Snowball sampling?

Answer 15

• where initial repsondents are found and then additional respondents are obtained from information provided by the initial repsondents

Question 16

What are non-probability methods best for?

Answer 16

Projects with financial and human rosurce constraints

Question 17

What is time location sampling?

Answer 17

Expert interviews help determine locations and times when prospects meet, face to face interviews are attempted.

Question 18

What do larger sample sizes cause?

Answer 18

More accuracy