c:ps1-1:ci_note
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rnorm2 <- function(n,mean,sd) {
mean + sd * scale(rnorm(n))
}
p1 <- rnorm2 (100000000, mean=70, sd=10)
set.seed(101)
s.size <- 16
s1 <- sample(p1, s.size, replace=T)
s1
m.s1 <- mean(s1)
sd.s1 <- sd(s1)
m.s1
sd.s1
se <- sd.s1/sqrt(s.size)
se2 <- 2*se
se3 <- 2*se
m.s1 - se2
m.s1 + se2
# or
c2 <- qnorm(.975)
c3 <- qnorm(.995)
c2
c3
se2 <- c2*se
se3 <- c3*se
m.s1 - se2
m.s1 + se2
> rnorm2 <- function(n,mean,sd) {
> mean + sd * scale(rnorm(n))
> }
>
> p1 <- rnorm2 (100000000, mean=70, sd=10)
>
> set.seed(101)
> s.size <- 16
> s1 <- sample(p1, s.size, replace=T)
> s1
[1] 67.33346 80.38354 71.51355 69.21986 60.04729 65.60540 69.31297 52.70064 76.02403
[10] 79.09528 60.57269 62.36968 69.86095 74.76315 64.24179 72.98447
> m.s1 <- mean(s1)
> sd.s1 <- sd(s1)
> m.s1
[1] 68.5018
> sd.s1
[1] 7.442683
>
> se <- sd.s1/sqrt(s.size)
> se2 <- se*2
> se3 <- se*3
>
> m.s1 - se2
[1] 64.78046
> m.s1 + se2
[1] 72.22314
>
> # or
> c2 <- qnorm(.975)
> c3 <- qnorm(.995)
> c2
[1] 1.959964
> c3
[1] 2.575829
>
> se2 <- se*c2
> se3 <- se*c3
> m.s1 - se2
[1] 64.85495
> m.s1 + se2
[1] 72.14864
>
>
c/ps1-1/ci_note.1732058261.txt.gz · Last modified: 2024/11/20 08:17 by hkimscil