Unit 4 - Statistics

Question 1

Types of Quantitative data

Answer 1

• Discrete: Can be counted, has a finite value. (E.g. Number of cats in this house)
• Continuous: Has no finite value (E.g. Age, Height, Weight, Temperature)

Question 2

Define Primary Data and its ads and dads

Answer 2

• Data collected ourselves.
• Ads: Being collected with specific purpose in mind. You know how the data was collected.

Question 3

Define Secondary data and its ads and dads

Answer 3

• Data collected by someone else.
• Dads: Could have been collected for a different purpose. Cannot know how data was collected. Unable to know validity of data.

Question 4

Define reliable data

Answer 4

If you repeat data collection, result will be similar.

Question 5

Define sufficient data

Answer 5

Enough data is available to support your conclusions.

Question 6

Define Target population

Answer 6

Population from where you want to take a sample.

Question 7

Define Sampling frame

Answer 7

List of items/people from which you can take your sample.

Question 8

Define Sampling unit

Answer 8

A single member from the sampling frame that is chosen to be sampled.

Question 9

Define Sampling variable

Answer 9

The variable under investigation. The characteristic you want to measure from each sampling unit.

Question 10

Define Sampling values

Answer 10

The possible values which the sampling variable can take.

Question 11

Explain Random Sampling and its ads and dads

Answer 11

• How it works: In a sampling frame, each item has an identifying number. Use random number generator. Every sample has equal chance of being chosen.
• Ads: Bias free, easy, cheap, equal chance.
• Dads: Not suitable with large population size, sampling frame required.

Question 12

Explain Stratified Sampling

Answer 12

• How it works: Population divided into groups (strata) and random sampling carried out in each group. Same proportion sampled from each group.
• Ads: Reflects population structure, guarantees proportional representation of groups within population
• Dads: Population must be clearly classified into distinct strata, selection within each stratum suffers same disadvantage as random sampling.

Question 13

Explain Systematic Sampling and its ads and dads

Answer 13

• How it works: required elements are chosen at regular intervals in ordered list.
• Ads: Simple and quick to use, suitable for large samples/populations.
• Dads: Sampling frame required, can be bias.

Question 14

Explain Quota sampling and its ads and dads

Answer 14

• How it works: Population is divided into groups according to characteristics. A quota of items/people in each group is set to try and reflect group’s proportion in the whole population. Interviewer selects actual sampling units.
• Ads: Allows small sample to still be representative of population, No sampling frame required, quick, easy, cheap.
• Dads: bias, dividing characteristics may be inaccurate, increasing scope increases time and cost, non-responses not recorded.