Two way anova with no interaction

apohle · 11-02-2009, 11:00 PM

Information-a research psychologist is interested in determining the effects of high versus low intensity shock on the the memorization of a hard versus easy list of nonsense syllables. Six subjects were randomly assigned to each of the four conditions. Subjects were presented with a list of 30 syllables, the response to each being correct or an error. Therefore, each subject makes between 0 and 30 errors. The number of errors made by each subject was as follows.
Low Shock Intensity High Shock Intensity
Easy List 9,16,16,11,12,10 15,13,9,9,8,12
Difficult list 10,12,18,16,17,17 19,18,18,23,14,16

a)construct a table of the sample means. Plot the means against shock intensity, including separate lines for the easy list and the hard list. Does the plot show any evidence of interaction?Does there appear to be differences in the mean number of errors made due to intensity of shock or the difficulty of the list of words.
Mean table-
LSI HSI Yi..
Easy list 12 11 11.5
Difficult list 15 18 16.5
Y.j. 13.5 14.5

looking at the plot I found that there is evidence of interaction because the lines are not parallel. I do not understand what they mean by "differences in the mean number of errors" what are the mean number of errors?

jamesmartinn · 11-03-2009, 10:34 AM

The mean number of errors (on the test of 30 syllabols) is your dependent variable. They've asked does there appear to be any differences for each variable (e.g., main effects). You've computed the marginal means and yes there does appear to be some difference for each variable:

Easy (11.5) > Hard (16.5) in terms of mean errors.
High Shock (14.5) > Low Shock (13.5) in terms of mean errors.

Whether these differences in mean errors are significant, requires you to actually compute the anova however.

11-02-2009, 11:00 PM	#1
apohle Junior Member Join Date: Nov 2009 Posts: 1 Thanks: 0 Thanked 0 Times in 0 Posts	Two way anova with no interaction Information-a research psychologist is interested in determining the effects of high versus low intensity shock on the the memorization of a hard versus easy list of nonsense syllables. Six subjects were randomly assigned to each of the four conditions. Subjects were presented with a list of 30 syllables, the response to each being correct or an error. Therefore, each subject makes between 0 and 30 errors. The number of errors made by each subject was as follows. Low Shock Intensity High Shock Intensity Easy List 9,16,16,11,12,10 15,13,9,9,8,12 Difficult list 10,12,18,16,17,17 19,18,18,23,14,16 a)construct a table of the sample means. Plot the means against shock intensity, including separate lines for the easy list and the hard list. Does the plot show any evidence of interaction?Does there appear to be differences in the mean number of errors made due to intensity of shock or the difficulty of the list of words. Mean table- LSI HSI Yi.. Easy list 12 11 11.5 Difficult list 15 18 16.5 Y.j. 13.5 14.5 looking at the plot I found that there is evidence of interaction because the lines are not parallel. I do not understand what they mean by "differences in the mean number of errors" what are the mean number of errors?

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11-03-2009, 10:34 AM	#2
jamesmartinn Senior Member Join Date: Jun 2007 Posts: 256 Thanks: 12 Thanked 12 Times in 12 Posts	The mean number of errors (on the test of 30 syllabols) is your dependent variable. They've asked does there appear to be any differences for each variable (e.g., main effects). You've computed the marginal means and yes there does appear to be some difference for each variable: Easy (11.5) > Hard (16.5) in terms of mean errors. High Shock (14.5) > Low Shock (13.5) in terms of mean errors. Whether these differences in mean errors are significant, requires you to actually compute the anova however.