Variation and Sampling

Question 1

What is discrete and continous variation?

Answer 1

Discrete - Where there is a limited number of possible characteristic groups (e.g. blood type, gender).
Continuous - Where the characteristivd gradually change across a range of values (e.g. height, weight).

Question 2

What makes a sample representative?

Answer 2

It must take into account the extent of natural variation in the popilation and how the population as a whole is distributed. The greater the variation, the larger the sample size should be.

Question 3

What should a representative sample share with the whole population?

Answer 3

The same mean and the same degree of variation about the mean.

Question 4

Describe random sampling.

Answer 4

Each member of the population has an equal chance of being selected. Shows little or no bias.

Question 5

Describe systematic sampling.

Answer 5

Members of the population are selected at regular intervals.

Question 6

Describe stratified sampling.

Answer 6

The population is divided into catergories that are then samplet proportionally.