Alverno CollegeStatistics

Why learn statistics?What are the different research designs used to collect data?

Why Learn Statistics?Maybe the department has it wrong

Priorities for Part IDefinition of StatisticsPopulations vs. SampleDescriptive Statistics vs. Inferential StatisticsExperimental, Quasi-Experimental, Correlational

DesignsIndependent , Quasi-Independent, Dependent

VariablesControl vs. Experimental GroupsTypes of MeasurementStatistical Notation

What types of research questions do we ask?(Theoretical Reasoning: Analysis and Developing a Global Perspective)

What types of research questions do we ask?What types of responses are observed?

(Descriptive Statistics)

What types of research questions do we ask?What conclusions can I make about a

population based on the sample data?

(Inferential Statistics)

What types of research questions do we ask?How do groups differ from each other on a specific variable?

Comparing Groups- based on different characteristics

What types of research questions do we ask?How do groups differ from each other on a specific variable?

Comparing Groups- based on different conditions

with a rebellious peerwithout a rebellious peer

Stanley Milgram Experiments

Prisoner Guard

The Standard Prison ExperimentZimbardo

What types of research questions do we ask?Which variables help us predict specific behaviors?

(Analyze Relationships between Variables)

What do final reports of data look like?Forget what you know about study habitsImproving the Writing Skills of StudentsTexting = Epic FailThe Status of Girls in Wisconsin

A PlanTo conduct research, we need a plan!

Types of Research DesignsExperimental

Administration of condition by the researcher Cause and Effect

Quasi- Experimental Compares groups based on pre-existing

characteristics Describes Differences

Correlational Collecting Information about a specific behavior Exploring Relationships among Variables

Components of an Experimental Research Design

Independent variable: The variable the researcher will test (control).

Dependent variable: Researchers will measure responses on the dependent variable.

Components of a Quasi -Experimental Research Design

Quasi- Independent variable: The variable the researcher uses to create different groups from pre-existing characteristics.

Dependent variable:Researchers will measure responses on the

dependent variable.

Components of a Correlational Research DesignTypically we don’t distinguish between

Independent/Dependent VariablesWe examine how variables relate to each

otherNegative correlation

As one variable increases the other decreasesPositive correlation

As one variable increases the other also increases

Correlation Coefficient (Cont’d)

What is the relationship between?

Gasoline prices and grocery prices?

Stress and depression?

Depression and job productivity?

Partying and grades?

Study time and grades?

Correlation (cont’d)

Correlation coefficient “r”

0 to +.3 = weak +.4 to +.6 = medium +.7 to +1.0 = strong

0 to -.3 = weak -.4 to -.6 = medium -.7 to -1.0 = strong

-1 0 +1

DirectInverseWeak

Strong Strong

Scatterplots

Correlation between two variables plotted on graph

A diagonal line = closely related variables

Examples of Scatterplots

SAT & GPA Correlation

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

0 200 400 600 800 1000 1200

SAT

GPA

Missed Classes & GPA

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

0 1 2 3 4 5 6 7 8 9

Missed classes

GPA

Scatterplots (cont’d)

What correlation (r ) do you think this graph has?

How about this correlation?

More Scatterplots

What might this correlation be? This correlation?

Identifying Research DesignsGravetter & Wallnau 8th edition:

Page 19, learning checkPages 33-34

1, 5, 7, 9, 11, 15a & 15b, 17aIn Class Activity

Reading Published Articles Findling, et al. (2006) Gringerich & Lineweaver (2012)

HomeworkGravetter & Wallnau pages 33-346, 8, 10a, 12, 16

Experimental Design

Correlation Design

Quasi-Experimental

Research

Comparing Groups

Cause and Effect

Relationships

Having a plan

Choose the best matches

Independent Variable

Quasi-Independent Variable

Dependent Variable

Responses or Observations

Manipulated

Used to Group Participants

Choose the best matches