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)
a1 <- qnorm(.95)
a2 <- qnorm(.975)
a3 <- qnorm(.995)
a1
a2
a3
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 <- se*2
se3 <- se*3
m.s1 - se2
m.s1 + se2
# or
se2 <- se*a2
se3 <- se*a3
m.s1 - se2
m.s1 + se2
> a1 <- qnorm(.95) > a2 <- qnorm(.975) > a3 <- qnorm(.995) > a1 [1] 1.644854 > a2 [1] 1.959964 > a3 [1] 2.575829 > > 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 > se2 <- se*a2 > se3 <- se*a3 > m.s1 - se2 [1] 64.85495 > m.s1 + se2 [1] 72.14864 > >
c/ps1-1/ci_note.1732057590.txt.gz · Last modified: by hkimscil