Fri, April 16, 2010 2:31:53 PM
Fw: statistica
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Tibheriu Vasile <djsilasdj@yahoo.com>  [Chat now]
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tema3.txt (2KB); lq.dat (1KB)


----- Forwarded Message ----
From: Tibheriu Vasile <djsilasdj@yahoo.com>
To: vlad_2901@yahoo.com; ionutandone@yahoo.com; bitza_b@yahoo.com; litewave0@yahoo.com
Sent: Fri, April 16, 2010 2:15:11 PM
Subject: statistica




Inline Attachment Follows: tema3.txt

> iq.data<-read.table("C:\\Documents and Settings\\Student\\Desktop\\lq.dat",col.names=c("dep","iq","bp"))
> iq.data



> iqnd<-iq.data[iq.data[,"dep"]=="ND","iq"]
> iqnd
[1] 103 124 124 104  92 124  99  92 116  99 117  89 125 127 112  48 139 118 106 117 123 118 117 141
[25] 124 110  98 109 120 127 103 118 117 115 119 117  92 101 119 144 119 127 113 127 103 128  86 112
[49] 115 117  99 110 117  96 118 126 126  89 102 134  93 115  99 122 106 124 100 114 121 119 108 110
[73] 127 118 107 110 114 118 114

> iqd<-iq.data[iq.data[,"dep"]=="D","iq"]
> iqd
[1]  96  22  81 100 107 129  84 101 139 111  99 123 102 101 121

> summary(iqnd)
  Min. 1st Qu.  Median    Mean 3rd Qu.    Max.
  48.0  103.5  116.0  112.8  121.5  144.0
> summary(iqd)
  Min. 1st Qu.  Median    Mean 3rd Qu.    Max.
  22.0    97.5  101.0  101.1  116.0  139.0
>
> boxplot(iqnd,iqd)
> par(mfrow=c(2,1))
> hist(iqnd)
> hist(iqd)
> > qqnorm(iqd)
> qqline(iqd)
> qqnorm(iqnd)
> qqline(iqd)
> > var(iqnd)
[1] 205.5044
> var(iqd)
[1] 729.2095

var.test(iqnd,iqd)

var(iqnd[iqnd>50])
var(iqd[iqd>50])

> > var.test(iqnd[iqnd>50],iqd[iqd>50])

        F test to compare two variances

data:  iqnd[iqnd > 50] and iqd[iqd > 50]
F = 0.5664, num df = 77, denom df = 13, p-value = 0.1283
alternative hypothesis: true ratio of variances is not equal to 1
95 percent confidence interval:
0.2102836 1.1765891
sample estimates:
ratio of variances
        0.5664063

>  t.test(iqnd[iqnd>50],iqd[iqd>50])

> plot(iq.data[,"iq"],iq.data[,"bp"])
abline(lsfit(iq.data[,"iq"],iq.data[,"bp"]))
cor.test(iq.data[,"iq"],iq.data[,"bp"])