You will now determine the number of levels there are in the problem you are working on.

Your options will be:

Your options will be:

Two Levels

Three or More Levels

Levels mean the number of conditions within an independent variable.

Why are levels important in statistics?

As you will see, the number of levels of the independent variable will determine the type of statistical analysis method we use!

As you will see, the number of levels of the independent variable will determine the type of statistical method you will use!

You will now see illustrations of what we mean by the concept of “levels” or “number of conditions within an independent variable”

Consider the following research question:

A researcher wants to analyze if there are statistically significant differences among religious groups (Catholics, Buddhists, & Muslims) in terms of public religious devotion.

First, let’s identify the dependent and independent variables.

The dependent variable is:

The dependent variable is:

A researcher wants to analyze which religious group (Catholics, Buddhists, & Muslims) has significantly greater public religious devotion.

The dependent variable is:

A researcher wants to analyze which religious group (Catholics, Buddhists, & Muslims) has significantly greater public religious devotion.

The independent variable is:

The independent variable is:

A researcher wants to analyze which religious group (Catholics, Buddhists, & Muslims) has significantly greater public religious devotion.

The independent variable is:

A researcher wants to analyze which religious group (Catholics, Buddhists, & Muslims) has significantly greater public religious devotion.

Now we look for levels or conditions within the independent variable.

Now we look for levels or conditions within the independent variable.

A researcher wants to analyze which religious group (Catholics, Buddhists, & Muslims) has significantly greater public religious devotion.

Now we look for levels or conditions within the independent variable.

A researcher wants to analyze which religious group (Catholics, Buddhists, & Muslims) has significantly greater public religious devotion.

Now we look for levels or conditions within the independent variable.

A researcher wants to analyze which religious group (Catholics, Buddhists, & Muslims) has significantly greater public religious devotion.

Now we look for levels or conditions within the independent variable.

A researcher wants to analyze which religious group (Catholics, Buddhists, & Muslims) has significantly greater public religious devotion.

Now we look for levels or conditions within the independent variable.

A researcher wants to analyze which religious group (Catholics, Buddhists, & Muslims) has significantly greater public religious devotion.

Now we look for levels or conditions within the independent variable.

A researcher wants to analyze which religious group (Catholics, Buddhists, & Muslims) has significantly greater public religious devotion.

3 Levels

Three levels

A researcher wants to analyze which religious group (Catholics, Buddhists, & Muslims) has significantly greater public religious devotion.

Three levels within the independent variable

A researcher wants to analyze which religious group (Catholics, Buddhists, & Muslims) has significantly greater public religious devotion.

So the number of levels would be:

So the number of levels would be:

Two Levels

Three or More Levels

Here is another study

There is no significant difference between the average hours of drowsiness of a group of truck drivers who use country music to stay awake and another group of truck drivers who do not listen to country music.

What is the dependent variable?

What is the dependent variable?

There is no significant difference between the average hours of drowsiness of a group of truck drivers who use country music to stay awake and another group of truck drivers who do not listen to country music.

What is the dependent variable?

There is no significant difference between the average hours of drowsiness of a group of truck drivers who use country music to stay awake and another group of truck drivers who do not listen to country music.

What is the independent variable?

What is the independent variable?

There is no significant difference between the average hours of drowsiness of a group of truck drivers who use country music to stay awake and another group of truck drivers who do not listen to country music.

Actually, the independent variable is not stated.

There is no significant difference between the average hours of drowsiness of a group of truck drivers who use country music to stay awake and another group of truck drivers who do not listen to country music.

But, we can determine the independent variable by looking at the groups.

There is no significant difference between the average hours of drowsiness of a group of truck drivers who use country music to stay awake and another group of truck drivers who do not listen to country music.

It appears that there are two groups

There is no significant difference between the average hours of drowsiness of a group of truck drivers who use country music to stay awake and another group of truck drivers who do not listen to country music.

It appears that there are two groups

There is no significant difference between the average hours of drowsiness of a group of truck drivers who use country music to stay awake and another group of truck drivers who do not listen to country music.

Group 1

It appears that there are two groups

There is no significant difference between the average hours of drowsiness of a group of truck drivers who use country music to stay awake and another group of truck drivers who do not listen to country music.

Group 2

So what is the difference between these two groups?

So what is the difference between these two groups?

- One group listens to country music

So what is the difference between these two groups?

- One group listens to country music

- The other group does not listen to country music

So what is the difference between these two groups?

- One group listens to country music

- The other group does not listen to country music

An independent variable simply provides a description of these two groups.

So what is the difference between these two groups?

- One group listens to country music

- The other group does not listen to country music

In this case: Country Music Listening

So, let’s go back to the problem

Now we know that the independent variable is country music listening.

There is no significant difference between the average hours of drowsiness of a group of truck drivers who use country music to stay awake and another group of truck drivers who do not listen to country music.

At this point the levels are easy to see:

There is no significant difference between the average hours of drowsiness of a group of truck drivers who use country music to stay awake and another group of truck drivers who do not listen to country music.

At this point the levels are easy to see:

There is no significant difference between the average hours of drowsiness of a group of truck drivers who listen country music to stay awake and another group of truck drivers who do not listen to country music.

At this point the levels are easy to see:

There is no significant difference between the average hours of drowsiness of a group of truck drivers who listen country music to stay awake and another group of truck drivers who do not listen to country music.

At this point the levels are easy to see:

There is no significant difference between the average hours of drowsiness of a group of truck drivers who listen country music to stay awake and another group of truck drivers who do not listen to country music.

2 Levels

Here is a way to visualize this:

Independent Variable:

Country Music Listening

Independent Variable:

Country Music Listening

Those who listen Those who DON’T listen

2 levels / conditions

So the number of levels would be:

So the number of levels would be:

Two Levels

Three or More Levels

Sometimes there will be two independent variables.

Each independent variable will have it’s own levels.

Let’s see an example:

Is there a difference in 8th grade standardized scores based on socio-economic status (wealthy, upper middle class, lower middle class, and below the poverty line) and / or reported church attendance (attender or non attender)?

What is the dependent variable?

What is the dependent variable?

Is there a difference in 8th grade standardized scores based on socio-economic status (wealthy, upper middle class, lower middle class, and below the poverty line) and / or reported church attendance (attender or non attender)?

What is the dependent variable?

Is there a difference in 8th grade standardized scores based on socio-economic status (wealthy, upper middle class, lower middle class, and below the poverty line) and / or reported church attendance (attender or non attender)?

What are the independent variables (IVs)?

What are the independent variables (IVs)?

Is there a difference in 8th grade standardized scores based on socio-economic status (wealthy, upper middle class, lower middle class, and below the poverty line) and / or reported church attendance (attender or non attender)?

What are the independent variables (IVs)?

Is there a difference in 8th grade standardized scores based on socio-economic status (wealthy, upper middle class, lower middle class, and below the poverty line) and / or reported church attendance (attender or non attender)?1st IV

What are the independent variables (IVs)?

Is there a difference in 8th grade standardized scores based on socio-economic status (wealthy, upper middle class, lower middle class, and below the poverty line) and / or reported church attendance (attender or non attender)?

2nd IV

What are the Levels?

What are the Levels?

Is there a difference in 8th grade standardized scores based on socio-economic status (wealthy, upper middle class, lower middle class, and below the poverty line) and / or reported church attendance (attender or non attender)?

For socio-economic status- level 1 = wealthy- level 2 = upper middle class- level 3 = lower middle class- level 4 = below the poverty line

Is there a difference in 8th grade standardized scores based on socio-economic status (wealthy, upper middle class, lower middle class, and below the poverty line) and / or reported church attendance (attender or non attender)?

For socio-economic status- level = wealthy- level 2 = upper middle class- level 3 = lower middle class- level 4 = below the poverty line

Is there a difference in 8th grade standardized scores based on socio-economic status (wealthy, upper middle class, lower middle class, and below the poverty line) and / or reported church attendance (attender or non attender)?

For socio-economic status- level = wealthy- level = upper middle class- level 3 = lower middle class- level 4 = below the poverty line

Is there a difference in 8th grade standardized scores based on socio-economic status (wealthy, upper middle class, lower middle class, and below the poverty line) and / or reported church attendance (attender or non attender)?

For socio-economic status- level = wealthy- level = upper middle class- level = lower middle class- level 4 = below the poverty line

Is there a difference in 8th grade standardized scores based on socio-economic status (wealthy, upper middle class, lower middle class, and below the poverty line) and / or reported church attendance (attender or non attender)?

For socio-economic status- level = wealthy- level = upper middle class- level = lower middle class- level = below the poverty line

Is there a difference in 8th grade standardized scores based on socio-economic status (wealthy, upper middle class, lower middle class, and below the poverty line) and / or reported church attendance (attender or non attender)?

For socio-economic status- level = wealthy- level = upper middle class- level = lower middle class- level = below the poverty line

Is there a difference in 8th grade standardized scores based on socio-economic status (wealthy, upper middle class, lower middle class, and below the poverty line) and / or reported church attendance (attender or non attender)?

4 Levels

For church attendance- level 1 = those who attend- level 2 = those who do not attend- level 3 = lower middle class- level 4 = below the poverty line

Is there a difference in 8th grade standardized scores based on socio-economic status (wealthy, upper middle class, lower middle class, and below the poverty line) and / or reported church attendance (attender or non attender)?

For church attendance- level = those who attend- level 2 = those who do not attend- level 3 = lower middle class- level 4 = below the poverty line

Is there a difference in 8th grade standardized scores based on socio-economic status (wealthy, upper middle class, lower middle class, and below the poverty line) and / or reported church attendance (attender or non attender)?

For church attendance- level = those who attend- level = those who do not attend- level 3 = lower middle class- level 4 = below the poverty line

Is there a difference in 8th grade standardized scores based on socio-economic status (wealthy, upper middle class, lower middle class, and below the poverty line) and / or reported church attendance (attender or non attender)?

For church attendance- level = those who attend- level = those who do not attend- level 3 = lower middle class- level 4 = below the poverty line

Is there a difference in 8th grade standardized scores based on socio-economic status (wealthy, upper middle class, lower middle class, and below the poverty line) and / or reported church attendance (attender or non attender)?

2 Levels

Let’s see this visually:

Independent Variable:

Socio-economic Status

Independent Variable:

Socio-economic Status

Wealthy

Independent Variable:

Socio-economic Status

Upper Middle Class

Wealthy

Independent Variable:

Socio-economic Status

Upper Middle Class

WealthyLower

Middle Class

Independent Variable:

Socio-economic Status

Upper Middle Class

WealthyBelow

Poverty LineLower

Middle Class

Independent Variable:

Socio-economic Status

Upper Middle Class

WealthyBelow

Poverty LineLower

Middle Class

4 levels

Next Independent Variable:

Independent Variable:

Church Attendance

Non-attender

Independent Variable:

Church Attendance

Independent Variable:

Church Attendance

AttenderNon-attender

Independent Variable:

Church Attendance

AttenderNon-attender

2 levels

So the number of levels would be:

Upper Middle Class

Wealthy Below Poverty Line

Lower Middle Class

Independent Variable:Socio-economic Status

4 levels

Upper Middle Class

Wealthy Below Poverty Line

Lower Middle Class

Independent Variable:Socio-economic Status

4 levels

Upper Middle Class

Wealthy Below Poverty Line

Lower Middle Class

Independent Variable:Socio-economic Status

4 levels

AttenderNon-

attender

Independent Variable:Church Attendance

2 levels

Upper Middle Class

Wealthy Below Poverty Line

Lower Middle Class

Independent Variable:Socio-economic Status

4 levels

AttenderNon-

attender

Independent Variable:Church Attendance

2 levels

6 levels

So the number of levels would be:

Two Levels

Three or More Levels

In Summary:

Levels simply mean the number of conditions within an independent variable.

Here are a number of visual examples

Independent Variable

Socio-economic status

Independent Variable

Levels

Socio-economic status

Wealthy Upper Middle Class

Lower Middle Class

Poverty4 Levels

Socio-economic status

Independent Variable

Country Music Listening

Independent Variable

Levels

Country Music Listening

Those who DO

listen

Those who DON’Tlisten

2 Levels

Country Music Listening

Independent Variable

Religious AffiliationIndependent Variable

Levels

Religious Affiliation

Catholic Muslim Buddhist3 Levels

Religious Affiliation

Independent Variable

Independent Variable

Gender

Levels

Gender

Male Female2 Levels

Gender

How many levels does the problem you are working on have?

How many levels does the problem you are working on have?

Two Levels

Three or More Levels