##### Biometry Chapters 1 & 2

What are the 3 goals of biometry?

1. To do science

2. To evaluate other's work

3. To communicate

What are the 7 steps to the scientific method?

1. Observation

2. Question

3. Hypothesis

4. Prediction

5. Experiment

6. Analysis

7. Disseminate Results

Hypothesis?

An educated guess at an answer to a question about cause, mechanism, or function.

Alternative research hypothesis?

A different educated guess to the same question of your original hypothesis.

Prediction

What you would expect to find if a particular hypothesis is true

General prediction

A prediction expressed in broad general terms

Specific prediction

A prediction expressed in term of things you can measure

How do you write a prediction?

If - then statement

Independent variable

A variable whose variation does not depend on another variable

Dependent variable

A variable whose variation dependent on the variation of the independent variable. It is what is measured in the end of the experiment.

Synonyms for independent variable (3)

Predictor variable

Explanatory variable

Factor

Synonyms for dependent variable (3)

Test variable

Data variable

response variable

Population

A group of every individual in the world

Parameter

Average __________ of a population.

like height

Sample

A group representing the population

Statistic

A value that estimates the parameter

Three characteristics of a good sample

1. Large sample size (n>20)

2. Avoid bias

3. Independent measurements

A sample should have the __________ __________ as the population it is representing.

A sample should have the same characteristics as the population it is representing.

Power analysis

How to tell how large of a sample size you need.

Three types of measurements

1. Nominal/Qualitative

2. Ordinal/Rank

3. Scale/Quantitative

Nominal/Qualitative measurement

Categories that have no intrinsic order

- Male or female

- Blue or pink flowers

Ordinal/Rank measurement

Categories with order or ranking.

- Low, medium or high parasitic burden

- Freshmen, sophomores, juniors, or seniors

Scale/Quantitative measurement

Expressed by numbers or amount.

- Temperature, height, age, mass

Two types of scale/quantitative measurements.

1. Discrete

2. Continuous

Discrete measurement

Scale data generated by counting

- Counting the number of parasitic worms

Continuous measurement

Scale data generated by measuring

- Measuring the length of parasitic worms