Errors, Variability And Statistics

Question 1

Null hypothesis defintion

Answer 1

An explanation against your anticipated cause and effect based on action of chance alone
(Assume nothing special is happening)

Question 2

Probability theory definition

Answer 2

Probability of discrete events can be represented by the Poisson distribution (discrete)
- This is extended to represent a continuous equivalent - Gaussian distribution

Question 3

The normal curve characteristics

Answer 3

Parameters:
- mean
- standard deviation
- area under the curve of 1

Question 4

Standard deviation definition and key figures

Answer 4

SD: the root of the mean of the sum of the squared of the deviations (the extent to which the raw data deviates from the mean)

1SD encompasses 2/3 of data
2SD encompasses 95% of data
3SD encompasses 99% of data

Poisson estimate of SD = sqroot(mean)

Question 5

Central limit theorem

Answer 5

Tool whereby you compare means of samples and their standard deviation across a large population using a frequency histogram
- assumes that although raw data is unlikely to be normally distributed, it is likely that the distribution of means is

Question 6

Sources of variability

Answer 6

Noise
- instrumentation
- operator
- technique
Natural
Inaccurate reporting