eM2 Analysis

Question 1

What is independent/ dependent (unpaired/ paired) groups?

Answer 1

The last question in the statistical decision tree asks whether the groups that are being compared are dependent or independent. This question is asking whether each group is composed of the same subjects of interest, or if they are different.

Question 2

What is the difference between a parametric and non parametric test?

Answer 2

Parametric- data which is normally distributed

Non-parametric- data which is not normally distributed

Question 3

Which is better: parametric or non-parametric and why?

Answer 3

Parametric- they are easier to understand and analyses are more powerful/ less likely to incorrectly reject or fail to reject a hypothesis

Question 4

What is the paired and unpaired t-test?

Answer 4

Comparing means from two normally distributed samples either different variables from the same sample (paired) or the same variable from different samples (unpaired)

Question 5

What is the one-way ANOVA?

Answer 5

Compares parametric means of data from more than 2 samples. It can be for paired data (repeated measures, one-way ANOVA) or unpaired (one-way ANOVA)

Question 6

What is the two way ANOVA?

Answer 6

Compares two independent variables

Question 7

What is the MANOVA?

Answer 7

Multivariate ANOVA

Question 8

What is the problem with a one way ANOVA and how do we get over this?

Answer 8

You cannot tell which sets of data of the 3+ samples show difference.

You need to use a (Tukey/Bonferonni) post hoc test

Question 9

What are the non parametric tests and what data are they used for?

Answer 9

Wilcoxon- non-parametric, paired, two sample

Mann-Whitney U- non-parametric, unpaired, two sample

Friedman- non parametric, paired, 3+ sample

Kruskal Wallis- non-parametric, unpaired, 3+ sample

Question 10

What type of data are non parametric tests generally used for?

Answer 10

Quantitative

Question 11

What do you report?

Answer 11

Only the p value

Question 12

What is a correlation?

Answer 12

A relationship between two data sets

Question 13

What are the types of correlation test?

Answer 13

Pearson (Parametric)

Spearman rank (Not parametric)

Question 14

What is an r-value?

Answer 14

Part of the Pearson test. It is a correlation coefficient telling you how strong the relationship is. It is between -1 and +1.

Question 15

What is a p-value in Pearson’s correlation test?

Answer 15

Tells you how reliable the R value is.

Question 16

What is an r^2 value?

Answer 16

Tells you how close the data is fitted to a correlation line.

Question 17

What are the lower boundaries for correlation in Pearson’s?

Answer 17

0- very low

0. 2-low
1. 4- reasonable
2. 6- High
3. 8- Very high

Question 18

What is the Spearman Rank test?

Answer 18

Finds correlation of non-parametric data; it identifies linear trends.

Question 19

What does the Spearman Rank show?

Answer 19

Spearman’s Rho (p) showing how strong a relationship is.

P value showing how reliable rho is (smaller is better)

Question 20

What is regression?

Answer 20

Regression quantifies the association between the two variables (the impact changing one variable will have on the other)

Question 21

What is the equation of regression?

Answer 21

y=a+bx

a= y intercept

b= gradient

Question 22

What is Chi-squared?

Answer 22

Tests similarities or differences between two discrete (categorical) variables.

Question 23

What will Xsquared be if the observed and expected frequencies are the same?

Answer 23

0- the higher the value, the bigger the difference

P-value is used to show significance