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--- r:general_statistics [2019/10/10 22:46] – [Forming a Confidence Interval for a Mean] hkimscil
+++ r:general_statistics [2019/10/10 22:56] (current) – [Forming a Confidence Interval for a Mean] hkimscil
@@ Line 512: / Line 512: @@
 > SE
 [1] 2.458358
-> E <- qt(.975, df=n-1)*SE
+## qt fun: qt(prob, df) zscore 2점에 해당하는 점수는?
+> qtv <- qt(.975, df=n-1)
+> qtv
+[1]
+## qtv는 2에 해당하는 95퍼센트 CL
+## 이 때의 CI는
+> E <- qtv*SE
 > E
 [1] 4.940254
@@ Line 520: / Line 526: @@
 </code>
-<code>> t.test(x)
+<code>
+> t.test(x, mu=98)
 	One Sample t-test
 data:  x
-t = 39.052, df = 49, p-value < 2.2e-16
+t = 0.37089, df = 49, p-value = 0.7123
-alternative hypothesis: true mean is not equal to 0
+alternative hypothesis: true mean is not equal to 98
 percent confidence interval:
-.0636 100.9441
+.32303 103.34143
 sample estimates:
 mean of x
-.00386
+.83223
+> t.test(x, mu=100)
+	One Sample t-test
+data:  x
+t = -0.52043, df = 49, p-value = 0.6051
+alternative hypothesis: true mean is not equal to 100
+percent confidence interval:
+.32303 103.34143
+sample estimates:
+mean of x
+.83223
+> t.test(x, mu=95)
+	One Sample t-test
+data:  x
+t = 1.7079, df = 49, p-value = 0.09399
+alternative hypothesis: true mean is not equal to 95
+percent confidence interval:
+.32303 103.34143
+sample estimates:
+mean of x
+.83223
+>
 </code>