Aggregated Likert scale summary data - z-test?

[Math Is Hard]

<Moderator's note: Moved from a homework forum.>

1. Homework Statement
I have some summarized Likert scale data from a report and my co-workers want to know what kind of comparison analysis we could do with it. I don't have the raw data.
Most of the questions are on a 7-point scale (Strongly disagree, disagree, slightly disagree, neither agree nor disagree, slightly agree, agree, strongly agree).
I have the number of responders for each group and I know the number of responders in each category. The report groups the responders into number and percentage who chose one of the 3 "agree" categories. It looks similar to my attachment.

Homework Equations

I'm wondering if I can use a z test for proportions to compare the groups and see if they are significantly different. I'm attaching a sample that looks similar to the data I have to work with.

The Attempt at a Solution

I was looking at an online calculator here: http://www.socscistatistics.com/tests/ztest/Default2.aspx
Thanks!

 

[jim mcnamara]

http://blog.minitab.com/blog/advent...em-data-two-sample-t-test-versus-mann-whitney

I thought that the parametric test versus non-parametric test decision was a done deal. I guess not. This article (for minitab) discusses the use of both and asserts either one is okay. Apparently you can setup, run analysis, and see which statistical methodology is more likely to be reliable. Avoiding Type I error, for example.. Meaning the door can swing both ways depending on the data set.

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