master
Vikas Rawal 6 years ago
parent 1f0c3ace84
commit 23ef422130

@ -1,3 +1,3 @@
version https://git-lfs.github.com/spec/v1
oid sha256:a2c03497f7a23fda4d406bffd38f632c3131e924857dd32fd9ca45c27f043c63
size 175928
oid sha256:3a1bdd5e69d2c9d15bac557524888eb11f802d48433b1ef7f786f5c99cda8319
size 175327

BIN
bsample3.png (Stored with Git LFS)

Binary file not shown.

@ -49,7 +49,7 @@
paste("Sample size 5: mean = ",
round(mean(t1$meancol)),
"; stdev = ",
round(sqrt(var(t1$meancol))),sep="")->lab
round(sd(t1$meancol)),sep="")->lab
p+annotate("text",x=450,y=0.030,label=lab,colour="blue")->p
p
@ -67,7 +67,7 @@
paste("Sample size 20: mean = ",
round(mean(t0$meancol)),
"; stdev = ",
round(sqrt(var(t0$meancol))),sep="")->lab
round(sd(t0$meancol)),sep="")->lab
p+annotate("text",x=450,y=0.033,label=lab,colour="darkolivegreen")->p
p
@ -85,7 +85,7 @@
paste("Sample size 50: mean = ",
round(mean(t$meancol)),
"; stdev = ",
round(sqrt(var(t$meancol))),sep="")->lab
round(sd(t$meancol)),sep="")->lab
p+annotate("text",x=450,y=0.036,label=lab,colour="red")->p
p
@ -103,7 +103,7 @@
paste("Sample size 200: mean = ",
round(mean(t4$meancol)),
"; stdev = ",
round(sqrt(var(t4$meancol))),sep="")->lab
round(sd(t4$meancol)),sep="")->lab
p+annotate("text",x=450,y=0.039,label=lab,colour="pink")->p
p
#+end_src
@ -113,13 +113,14 @@
+ $Standard.error = \frac{\sigma}{\sqrt{mean}}$
| Standard deviation of population ($\sigma$) | 130 |
| Standard errors of samples of size | |
| 5 | 58 |
| 20 | 29 |
| 50 | 18 |
| 200 | 9 |
| Variable | Value |
|---------------------------------------------+-------|
| Standard deviation of population ($\sigma$) | 130 |
| Standard errors of samples of size | |
| 5 | 58 |
| 20 | 29 |
| 50 | 18 |
| 200 | 9 |
@ -140,7 +141,7 @@
library(ggplot2)
worker->t9
(t9$wage-mean(t9$wage))/sqrt(var(t9$wage))->t9$wage
(t9$wage-mean(t9$wage))/sd(t9$wage)->t9$wage
ggplot(t9,aes(wage))+geom_density(colour="black",size=1)->p
p+scale_y_continuous(limits=c(0,0.75))->p
p+scale_x_continuous(limits=c(-15,15)
@ -159,7 +160,7 @@
c(t1,mean(s1$wage))->t1
}
data.frame(sno=c(1:10000),meancol=(t1-mean(worker$wage))/sqrt(var(t1)))->t1
data.frame(sno=c(1:10000),meancol=(t1-mean(worker$wage))/sd(t1))->t1
p+geom_density(data=t1,aes(meancol),colour="blue",size=1)-> p
p
@ -172,7 +173,7 @@
c(t0,mean(s1$wage))->t0
}
data.frame(sno=c(1:10000),meancol=(t0-mean(worker$wage))/sqrt(var(t0)))->t0
data.frame(sno=c(1:10000),meancol=(t0-mean(worker$wage))/sd(t0))->t0
p+geom_density(data=t0,aes(meancol),colour="darkolivegreen",size=1)-> p
p
@ -185,7 +186,7 @@
c(t,mean(s1$wage))->t
}
data.frame(sno=c(1:10000),meancol=(t-mean(worker$wage))/sqrt(var(t)))->t
data.frame(sno=c(1:10000),meancol=(t-mean(worker$wage))/sd(t))->t
p+geom_density(data=t,aes(meancol),colour="red",size=1)-> p
p
@ -198,7 +199,7 @@
c(t4,mean(s1$wage))->t4
}
data.frame(sno=c(1:10000),meancol=(t4-mean(worker$wage))/sqrt(var(t4)))->t4
data.frame(sno=c(1:10000),meancol=(t4-mean(worker$wage))/sd(t4))->t4
p+geom_density(data=t4,aes(meancol),colour="pink",size=1)-> p
p
#+end_src
@ -220,7 +221,7 @@
worker[sex!=3,]->worker
worker->t9
(t9$wage-mean(t9$wage))/sqrt(var(t9$wage))->t9$wage
(t9$wage-mean(t9$wage))/sd(t9$wage)->t9$wage
ggplot(t9,aes(wage))+geom_density(colour="black",size=1)->p
p+scale_y_continuous(limits=c(0,0.75))->p
p+scale_x_continuous(limits=c(-15,15)
@ -236,19 +237,19 @@
rbind(t4,data.frame(
sno=i,
meancol=mean(s1$wage),
sterr=sqrt(var(s1$wage))/sqrt(samplesize)
sterr=sd(s1$wage)/sqrt(samplesize)
)
)->t4
}
(t4$meancol)/t4$sterr->t4$teststat
(t4$meancol)/sqrt(var(t4$meancol))->t4$teststat2
(t4$meancol)/sd(t4$meancol)->t4$teststat2
data.frame(modelt=rt(200000,samplesize-1,ncp=mean(t4$teststat)),modelnorm=rnorm(200000,mean=mean(t4$teststat2)))->m
var(t4$teststat)
var(m$modelt)
var(m$modelnorm)
var(t4$teststat2)
sd(t4$teststat)
sd(m$modelt)
sd(m$modelnorm)
sd(t4$teststat2)
mean(t4$teststat)
mean(m$modelt)
mean(m$modelnorm)
@ -260,18 +261,18 @@
p+geom_density(data=t4,aes(teststat),colour="blue",size=1)-> p
p+geom_density(data=m,aes(modelt),colour="darkolivegreen",size=1)->p
p+annotate("text",x=-30,y=0.42,
label=paste("Normal distribution, with standard deviation",round(sqrt(var(m$modelnorm)),2)),
label=paste("Normal distribution, with standard deviation",round(sd(m$modelnorm),2)),
colour="black",hjust=0)->p
p+annotate("text",x=-30,y=0.40,
label=paste("Statistic with known population variance, standard error =",
round(sqrt(var(t4$teststat2)),2)),
round(sd(t4$teststat2),2)),
colour="red",hjust=0)->p
p+annotate("text",x=-30,y=0.38,
label=paste("t distribution, with standard deviation =",round(sqrt(var(m$modelt)),2)),
label=paste("t distribution, with standard deviation =",round(sd(m$modelt),2)),
colour="darkolivegreen",hjust=0)->p
p+annotate("text",x=-30,y=0.36,
label=paste("Statistic with unknown population variance, standard error =",
round(sqrt(var(t4$teststat)),2)),
round(sd(t4$teststat),2)),
colour="blue",hjust=0)->p
p+scale_x_continuous(limits=c(-30,30))+theme_bw()->p
p

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