The Sniffy Paper

OK, we'll give you some supplemental information about the Sniffy Study that isn't available on other links that will help you with your paper.  We'll also tell you exactly what statistics to run. 

You were observing virtual rats in an operant chamber immediately after a period during which the rats received a series of unsignaled high insensitivity shocks (Condition A - details below) or received a series of trials in which there was no signal and no shock (Condition B) - that is, the virtual rats just hung-out in the chamber.  Based upon reading the paper you compressed, you must have deduced that we expect there to be more freezing in the post-shock observation period than after the period without shock.  That is, this should happen if virtual rats behave in the same way that published literature indicates live rats do. 

You know how many observations you made and what the inter-observation-interval was, so we don't need to do that again here.  You should tell the reader what behaviors you observed, but also tell the reader that you will only be reporting on Freezing.  All other behaviors will be considered non-Freezing. 

For inter-rater reliability, we calculated what we've been calling the percentage of possible agreements for Freezing observations.  That is, if either observer reported Freezing we counted that and divided this number into the number of times the observers agreed on Freezing (then multiplied by 100, of course).  We only looked at the Freezing ratings in the post-shock condition.  Only the post-shock condition was examined because Freezing virtually never happens in an unstressed animal and you can't get percent agreement when there's nothing to agree upon.  Dr. Baril has discussed inter-rater reliability in class and what level of agreement you need to say that things are pretty OK.  No observer pair had Percent Possible Agreement values of less than 81%  (Range 81-98%).  You'll see these data in the output you'll get from the supplemental syntax provided below.

The main analysis here was a t-test comparing the average (across the two observers) percentage of Freezing observed post-shock versus post-control.  The reason we averaged the number should be pretty obvious.  We also, independently for the shock/no shock conditions, used t-tests to compare freezing levels in the first 30 trials versus the 2nd 30 trials.  Why?  We were looking for evidence that freezing/fear decreased as time since the last shock passed.  Of course, we didn't expect a change in behavior for the no shock animals, since there was no change in their environment.  There was a big change in the shock condition animals - they now were getting no shocks.  You'll see that the latter two t-tests were not significant.  When discussing this lack of significance, you might suggest that 10 minutes was not enough time for fear to dissipate substantially - just a thought, it's your paper.  I sure don't want to see my words showing up in your paper.  I do want to see my mentoring/guidance show up there, however.

Ok...that's the big picture.

Below,  you'll find some details we haven't told you yet that may prove useful for your paper :
Good luck!!  (Supplemental syntax)




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