Maths & Stats

Question 1

Explain the T- Test

Answer 1

Is a statistical test used to compare the mean of two groups of data.

P-value is the probability value - the likelihood of finding a mean difference if there is no difference in the population.

If p-value is less than 0.05 it means that the test hypothesis is false and data is statistically different

Question 2

What are the statistical rules for control charts ?

Answer 2

Nelson’s Rules

R1 single point outside control limits
R2 8 consecutive points either side of the mean
R3 2 out of 3 results above or below control limits
R4 4 out of 5 results above or below control limits
R5 6 results in a row increasing or decreasing

Question 3

What is a shewhart chart?

Answer 3

Bar chart that identifies areas of focus by putting values in ascending or descending order

Question 4

What range would you expect for an assay method?

Answer 4

80-120% of test concentration

Question 5

What value would you expect for LOD?

Answer 5

Mean + 2 x Standard Deviations

Question 6

In what circumstances would you use the following statistical methods:
T test
2 sided t-test
F-test / ANOVA

Answer 6

T-test 1 one set of data against a specification

2 sided t-test- comparing two sets of data

F-test / ANOVA- multi-variate analysis- used to assess multiple factors