Using samples to describe populations

Question 1

What does statistic mean?

Answer 1

A value calculated from sample data.

- This value can vary between samples and is also, observable.

Question 2

What does parameter mean?

Answer 2

It is a value or characteristic of the whole population (ie: Population mean)
Usually fixed and can be unknown.

Question 3

What is the difference between statistic and parameter?

Answer 3

Statistics are adhered to sample data whereas parameter is adhered to population.

Question 4

What is point estimate?

Answer 4

This is when a sample statistic is used to estimate a population parameter.

Question 5

What is a sample distribution?

Answer 5

A sample is a set of observations from a defined population.
They have some form of distribution which may be described by sample statistics.

Question 6

What is a sampling distribution?

Answer 6

It is a distribution of the sample statistics (for example : mean / standard deviation etc)

Question 7

What is a sampling distribution dependent on?

Answer 7

Dependent on distribution of underlying population / sample size / sampling process / statistic used.

PROBABILITY DISTRIBUTION OF SAMPLE STATISTIC DERIVED FROM RANDOM SAMPLE

Question 8

What is the true population value?

Answer 8

Can be worked out when you know the distribution of the sample statistic and so you can quantify with precision.

Question 9

What is standard error?

Answer 9

The standard deviation of the sample mean.

Samples values are used as you don’t know the population value.

Question 10

What does the standard error give us a measure of?

Answer 10

Gives a measure of the spread of the sample means.

Question 11

What is the calculation for standard deviation?

Answer 11

√(1/𝑛 ∑1_(𝑖=1)^𝑛▒〖(𝑥_𝑖−𝑥̅)〗^2 )

Question 12

What is the significance of 1.96?

Answer 12

The value of 1.96 assumes there is a normal distribution.