Introduction

Question 1

What is rule 1?

Answer 1

State your objectives before you start your project

Question 2

What is rule 2?

Answer 2

Many questions cannot be answered due to biological hierarchy e.g. decreasing knowledge from molecular level to biosphere

Question 3

What is rule 3?

Answer 3

Just because a variable is measurable does not make it relevant to your study

Question 4

What is rule 4?

Answer 4

• Make an effort to collect sufficient data for proper statistical analysis e.g. number of replicates
• For monitoring studies = trade off between # of sample sites and # of replicates
• For experiments = trade off between # of factors and levels and # of replicates

Question 5

What is rule 5?

Answer 5

Balance sampling and experimental design if there is no reason not to i.e. strive for equal # of replicates for each sample location or treatment

Question 6

What is rule 6?

Answer 6

ALWAYS use controls in experimental studies (i.e. non treatment)

Question 7

What is rule 7?

Answer 7

• Get a representative unbiased (random) sample of the study population
• allows generalization (through inferential statistics) to the population of interest

Question 8

What is rule 8?

Answer 8

Conduct a preliminary survey

Question 9

What is rule 9?

Answer 9

Adjust the sample unit size to fit the organism sampled e.g.nested plot design

Question 10

What is rule 10?

Answer 10

Use stratified sampling (based on homogeneity of geography and density of organisms) or use blocked experimental design (based on physical gradients)

Question 11

What is rule 11?

Answer 11

• Test assumptions of parametric statistical analysis
• if the requirements CANNOT be met then: transform the data, use non parametric statistical analysis or re-sampling technique (e.g. Monte Carlo)

Question 12

What are the assumptions of parametric statistical analysis?

Answer 12

1. Independence
2. Homogeneity of Variance
3. Normality
4. No bias (randomness)

Question 13

What is rule 12?

Answer 13

Use a variety of statistical tests until you get the significant result you need

Question 14

What is rule 13?

Answer 14

Before starting decide on the number of significant figures to record (only applies when continuing an existing study)

Question 15

How to determine the adequate amount of significant figures?

Answer 15

Using the Sokal and Rohlf Method

Example: Max value = 80 mm and Min value = 20 mm

1. Determine the range = 60
2. Divide the range by 300 and 30

ANSWER: Measure to nearest 0.2 or up to 2 mm

Question 16

What is rule 14?

Answer 16

An ecological estimate needs measure of contributing errors e.g. mean +/- confidence interval

Question 17

What is rule 15?

Answer 17

Critical value used on environmental science is usually 0.05 (alpha)

It is SUGGESTED boundary for rejecting null hypothesis

Question 18

When is null hypothesis rejected or accepted (p-value)?

Answer 18

REJECTED when p-value LESS than 0.05

ACCEPTED when p-value GREATER than 0.05

Question 19

What is rule 16?

Answer 19

Statistical significance does NOT always equal biological significance

Question 20

What is rule 17?

Answer 20

Be aware and check mathematical model being applied

Question 21

What is rule 18?

Answer 21

Garbage in, garbage out….sloppy work will get you every time when you decide to do a statistical analysis and decision errors can occur

Question 22

What is a type 1 error?

Answer 22

Rejecting true NULL hypothesis (person not guilty but convicted)

Question 23

What is a type 2 error?

Answer 23

Rejecting true ALTERNATE hypothesis (person is guilty but not convicted)