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--- c:ma:2016:schedule:week09_answer [2016/11/09 09:45] – [E.g. 6] hkimscil
+++ c:ma:2016:schedule:week09_answer [2016/11/09 09:52] (current) – [E.g. 6] hkimscil
@@ Line 453: / Line 453: @@
 > smoke <- c(18,22,21,17,20,17,23,20,22,21)
 > nosmoke <- c(16,20,14,21,20,18,13,15,17,21)
-> t.test(smoke,nosmoke)
+> sn <- data.frame(smoke, nosmoke)
+> ss <- stack(sn)
+> plot(ss$values~ss$ind)
+</code>
+<code>> t.test(values$ss~ind$ss)
 	Welch Two Sample t-test
-data:  smoke and nosmoke
+data:  ss$values by ss$ind
-t = 2.2573, df = 16.376, p-value = 0.03798
+t = -2.2573, df = 16.376, p-value = 0.03798
 alternative hypothesis: true difference in means is not equal to 0
 percent confidence interval:
-.1628205 5.0371795
+ -5.0371795 -0.1628205
 sample estimates:
-mean of x mean of y
+mean in group nosmoke   mean in group smoke
-.1      17.5
+.5                  20.1
+>
 >