Week 8

Question 1

What is the difference between research hypothesis and statistical hypothesis?

Answer 1

Research hypothesis:
Educated guess about the answer that will be received from the experiment

Statistical hypothesis:
A proposal set up for statistical testing based around a specific outcome of the experiment

Question 2

What is the difference between population and sample and what are the symbols to denote mean and standard deviation?

Answer 2

Population:
The complete set of possible observations
Mean: u
SD: o

Sample:
A set of observations from the population
Mean: x
SD: d

Question 3

What does variation between samples depend on? (3)

Answer 3

• Variation in population, estimated using SD

- Sample size

Question 4

What is standard error of mean and how is it calculated? (3)

Answer 4

The sample mean can be an estimate of population mean
We can determine precision of the estimate by calculating standard error
SEM = SD/ root of n

Question 5

What is the 95% confidence interval and how can it be calculated?

Answer 5

95% confidence intervals give a range of values that mean we have a 95% chance of including the true population mean
Calculated by: mean +/- (1.96 x SEM)