2011_SS1_Homework 06 - Solutions

X2 3 n1 n2 10 5 estimated standard error of the mean

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Unformatted text preview: ject the null hypothesis using a two ­tailed test with ! = 0.05 ? ( X ! X2 ) 13 t( X1 ! X2 ) = 1 , t( X1 ! X2 ) = , t( X1 ! X2 ) = 2.60 s( X1 ! X2 ) 5 df = (n1 ­1)+(n2 ­1)=13, ! = 0.05 , t critical = ± 2.160 |tobserved| > |tcritical|, |2.60 | > |2.160|, Reject Null Hypothesis 17) Two separate samples receive two different treatments. The first sample has n=10 with SS=240, and the second sample has n=5 with SS = 150. Using this information, calculate the estimated standard error of the mean difference that we would use to calculate the t ­ statistic. Note: Remember that you must first calculate the pooled estimate of the variance. First: SS + SS1 2 240 + 150 2 390 s 2ooled = 1 , s pooled = , s pooled = , s 2ooled = 30 p p df1 + df2 9+4 13 Next, calculate the estimated standard error for the sample mean difference s2 s2 30 30 s( X1 ! X2 ) = pooled + pooled , s( X1 ! X2 ) = + , s( X1 ! X2 ) = 3 + 6 , s( X1 ! X2 ) = 3...
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This note was uploaded on 02/17/2013 for the course PSYC 60 taught by Professor Ard during the Fall '08 term at UCSD.

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