Take the McCroskey test yourself to see your apprehension level

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# Take the McCroskey test yourself to see your apprehension level - PowerPoint PPT Presentation

Take the McCroskey test yourself to see your apprehension level. This PowerPoint will walk through the comparison of means of the pre and post-tests. Remember the Types of Scales?. Nominal Data (Chi-square) classification data, e.g. m/f

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### Take the McCroskey test yourself to see your apprehension level

This PowerPoint will walk through the comparison of means of the pre and post-tests

McCroskey Scenario t-test

Remember the Types of Scales?

Nominal Data (Chi-square)

• classification data, e.g. m/f
• no ordering, e.g. it makes no sense to state that M > F
• arbitrary labels, e.g., m/f, 0/1, etc

Ordinal Data(t-test)

• ordered but differences between values are not important
• e.g., political parties on left to right spectrum given labels 0, 1, 2
• e.g., Likert scales, rank on a scale of 1..5 your degree of satisfaction
• e.g., restaurant ratings

Interval Data

• ordered, constant scale, but no natural zero
• differences make sense, but ratios do not (e.g., 30°-20°=20°-10°, but 20°/10° is not twice as hot!
• e.g., temperature (C,F), dates

Ratio Data

• ordered, constant scale, natural zero
• e.g., height, weight, age, length
• Quoted from http://www.stat.sfu.ca/~cschwarz/Stat-301/Handouts/node5.html

McCroskey Scenario t-test

Take McCroskey'sPRCA.  http://ww3.llcc.edu/speechsurvey/survey.aspx OR http://www.jamescmccroskey.com/measures/prca24.htm

Photo Source http://2.bp.blogspot.com/_27z_ybX1fcc/SafUfnpKgwI/AAAAAAAAAI4/nwRnSJx33dw/s400/speakerbestself.jpg

McCroskey Scenario t-test

Study
• Imagine that a group of 20 students enrolled in Dr. Cohn's public speaking course.  These students took McCroskey's test on the first day of their public speaking course.  Scores can range from 24-120, and a score above 65 suggests higher than average apprehension. Dr. Cohn is concerned that she has so many apprehensive students in the class.  Here are their scores:
• After one term of instruction, Dr. Cohn administered the test at the end of the course because she wanted to see if taking the course lowered student apprehension.
• In this case, there is a pre-post test for one group and the data on a scale.  Dr. Cohn asks you to calculate the results using a t-test.
• Is there a significant difference in the communication apprehension level of the class members before and after taking Dr. Cohn's course?

McCroskey Scenario t-test

First, you enter the data.

McCroskey Scenario t-test

McCroskey Scenario t-test

Select two

McCroskey Scenario t-test

Related data

McCroskey Scenario t-test

Normal Distribution

McCroskey Scenario t-test

The “Statistics Coach” help function guides you in what statistical test to use.

McCroskey Scenario t-test

What are the means to be compared? The average of the pretest, the average of the posttest. The calculator will figure this automatically as part of the t-test calculation.

• Add the 20 scores from the pretest = 1600
• Divide by 20 students in the class = 80 is the average or mean for the pretest.
• Add the 20 scores from the posttest = 1193
• Divide by 20 students in the class = 51

McCroskey Scenario t-test

Enter Data

McCroskey Scenario t-test

• Select “Analyze”
• Select “Compare Means,” which is what a t-test does.
• Select “Paired-Samples T Test,” which is what the Statistics Coach told us to do based on our answers to the various questions.

McCroskey Scenario t-test

If you don’t have SPSS, here is a calculator: http://www.physics.csbsju.edu/stats/t-test_bulk_form.html

McCroskey Scenario t-test

The standard deviation helps the researcher determine how much distance from the mean is typical and how much is considered significant.

McCroskey Scenario t-test

Using unpaired t-testt= 4.46 sdev= 20.2 degrees of freedom = 38 The probability of this result, assuming the null hypothesis, is less than .0001

• Scores are significantly lower after the course. (Remember, this is fictional research.)
• We can feel confident that completing the public speaking course helped lower student communication apprehension.

McCroskey Scenario t-test

### Hope you enjoyed this application practice!

McCroskey Scenario t-test