beginning statistics/ independent measures T test

been2uk

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Apr 25, 2010
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hello. Here is my question as follows:

The Shine Co believes that adding fragrance to a window cleaner will lead people to believe that it cleans better than an unscented one. 24 participants, 12 used unscented, 12 used scented. After 1 month of use the cleaners were rated. Higher scored indicate more effective cleaning. Here are the ratings;

unscented 6,5,7,5,6,8,4,7,5,6,6,7

scented 8,8,7,9,9,8,9,9,7,6,9,7

use alpha .01 and the six steps of hypothesis testing. If there is a significant difference, calculate effect size using d and r squared

I believe this is an independent measures T test using pooled variance, also 1 tailed

Ho: U 1</= U 2
H1: U 1> U 2
df =22
critical area on is 2.508 1 tailed test

pooled variance 1.18 s2p
Sm1-m2 =0.44
T = 4.54 or -4.54 this is my question is the T negative or positive? I thought positive which would cause me to reject the null and perform the effect sizes.
 
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