Categorizing Hypotheses

Can be categorized in different ways

1. Based on their formulation

Null Hypotheses and Alternate Hypotheses

2. Based on direction

Directional and Non-directional Hypothesis

3. Based on their derivation

Inductive and Deductive Hypotheses ---------------------------------------------------------------------------------------------------------------------

1. Based on their formulation : Null Hypotheses and Alternate Hypotheses

Null hypothesis always predicts that: no differences between the groups being

studied (e.g., experimental vs. control group) or no relationship between the

variables being studied.

By contrast, the alternate hypothesis always predicts that there will be a

difference between the groups being studied (or a relationship between the

variables being studied)

2. Based on direction : Directional Hypothesis and Non-directional Hypothesis

Simply based on the wording of the hypotheses we can tell the difference

between directional and non-directional

◦ If the hypothesis simply predicts that there will be a difference between the

two groups, then it is a non-directional hypothesis. It is non-directional

because it predicts that there will be a difference but does not specify how

the groups will differ.

◦ If, however, the hypothesis uses so-called comparison terms, such as

“greater,”“less,”“better,” or “worse,” then it is a directional hypothesis. It

is directional because it predicts that there will be a difference between the

two groups and it specifies how the two groups will differ

3. Based on their derivation : Inductive and Deductive Hypotheses(Theory

Building and Theory Testing)

Inductive hypothesis - a generalization based on observation

Deductive hypothesis - derived from theory

Example Hypotheses:

Key Info:

A hypothesis is an educated guess about how things work.

Most of the time a hypothesis is written like this: "If _____[I do this] _____, then

_____[this]_____ will happen." (Fill in the blanks with the appropriate information

from your own experiment.)

EXAMPLES:

"If I open the faucet [faucet opening size is the independent variable], then it will

increase the flow of water [flow of water is the dependent variable].

"Raising the temperature of a cup of water [temperature is the independent

variable] will increase the amount of sugar that dissolves [the amount of sugar is

the dependent variable]."

"If a plant receives fertilizer [having fertilizer is the independent variable], then it

will grow to be bigger than a plant that does not receive fertilizer [plant size is the

dependent variable]."

"If I put fenders on a bicycle [having fenders is the independent variable], then

they will keep the rider dry when riding through puddles [the dependent variable

is how much water splashes on the rider]."