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        <title>COMMunication&lt;br /&gt;RESearch.NET - b:head_first_statistics:estimating_populations_and_samples</title>
        <description></description>
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       <dc:date>2026-04-17T15:33:52+00:00</dc:date>
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        <title>COMMunication<br />RESearch.NET</title>
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        <dc:format>text/html</dc:format>
        <dc:date>2025-11-02T23:10:05+00:00</dc:date>
        <dc:creator>Anonymous (anonymous@undisclosed.example.com)</dc:creator>
        <title>mean_of_proportions_code</title>
        <link>http://www.commres.net/b/head_first_statistics/estimating_populations_and_samples/mean_of_proportions_code?rev=1762125005&amp;do=diff</link>
        <description>set.seed(101)
k &lt;- 1000
n &lt;- 100
p &lt;- 1/4
q &lt;- 1-p
# in order to clarify what we are doing
# X~B(n,p) 일 때, 100개의 검볼을 샘플링해서 
# red gumball을 세봤더니
rbinom(1,n,p) # 24개 였다라는 뜻 

# 아래는 이것을 1000번 (k번) 한 것
numbers.of.red.gumball &lt;- rbinom(k, n, p)
head(numbers.of.red.gumball)

# 아래처럼 n으로 (100개의 검볼이 총 숫자이므로) 
# 나눠주면 비율을 구할 수 있다
proportions.of.rg &lt;- numbers.of.red.gumball/n
ps.k &lt;- proportions.of.rg
head(ps.k)

mean.ps.k &lt;- mean(ps.k)
mean.ps.k
hist(ps.k)


####
set.seed(101)
k &lt;- 1000000
n &lt;- 100
p &lt;- 1/…</description>
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        <dc:date>2025-11-02T23:12:28+00:00</dc:date>
        <dc:creator>Anonymous (anonymous@undisclosed.example.com)</dc:creator>
        <title>mean_of_proportions_output</title>
        <link>http://www.commres.net/b/head_first_statistics/estimating_populations_and_samples/mean_of_proportions_output?rev=1762125148&amp;do=diff</link>
        <description>&gt; set.seed(101)
&gt; k &lt;- 1000
&gt; n &lt;- 100
&gt; p &lt;- 1/4
&gt; q &lt;- 1-p
&gt; # in order to clarify what we are doing
&gt; # X~B(n,p) 일 때, 100개의 검볼을 샘플링해서 
&gt; # red gumball을 세봤더니
&gt; rbinom(1,n,p) # 24개 였다라는 뜻 
[1] 24
&gt; 
&gt; # 아래는 이것을 1000번 (k번) 한 것
&gt; numbers.of.red.gumball &lt;- rbinom(k, n, p)
&gt; head(numbers.of.red.gumball)
[1] 18 27 27 22 23 26
&gt; 
&gt; # 아래처럼 n으로 (100개의 검볼이 총 숫자이므로) 
&gt; # 나눠주면 비율을 구할 수 있다
&gt; proportions.of.rg &lt;- numbers.of.red.gumball/n
&gt; ps.k &lt;- proportions.of.rg
&gt; head(ps.k)
[1] 0.18 0.27 0.27 0.22 0.23 …</description>
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        <dc:format>text/html</dc:format>
        <dc:date>2025-11-04T23:01:05+00:00</dc:date>
        <dc:creator>Anonymous (anonymous@undisclosed.example.com)</dc:creator>
        <title>sampling_distribution_of_means_in_r</title>
        <link>http://www.commres.net/b/head_first_statistics/estimating_populations_and_samples/sampling_distribution_of_means_in_r?rev=1762297265&amp;do=diff</link>
        <description>######
# sampling distribution of means 
######

ss &lt;- 30 # 30 bags of gums
m &lt;- 10 # average # of gums in a bag 
va &lt;- 1 #
sd &lt;- sqrt(va) # variance 

s.30 &lt;- rnorm(ss, m, sd)
s.30 # no natural numbers 
nm.s.30 &lt;- round(s.30,0) # natural numbers
sk &lt;- nm.s.30
sk
m.sk &lt;- mean(sk)
m.sk
v.sk &lt;- var(sk)
v.sk
sd.sk &lt;- sd(sk)
sd.sk

ss &lt;- 100 # size, from 30 to 100
set.seed(101)
iter &lt;- 10000
# means &lt;- c()
means &lt;- rep(NA, iter)
for (i in 1:iter) {
  m.bags &lt;- rnorm(ss,m,sd)
  nm.bags &lt;- round(m.bag…</description>
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        <dc:format>text/html</dc:format>
        <dc:date>2025-11-04T23:00:39+00:00</dc:date>
        <dc:creator>Anonymous (anonymous@undisclosed.example.com)</dc:creator>
        <title>sampling_distribution_of_means_in_r_output</title>
        <link>http://www.commres.net/b/head_first_statistics/estimating_populations_and_samples/sampling_distribution_of_means_in_r_output?rev=1762297239&amp;do=diff</link>
        <description>&gt; ######
&gt; # sampling distribution of means 
&gt; ######
&gt; 
&gt; ss &lt;- 30 # 30 bags of gums
&gt; m &lt;- 10 # average # of gums in a bag 
&gt; va &lt;- 1 #
&gt; sd &lt;- sqrt(va) # variance 
&gt; 
&gt; s.30 &lt;- rnorm(ss, m, sd)
&gt; s.30 # no natural numbers 
 [1] 10.227850  7.698154  9.373175  8.417650  8.048828  9.132477
 [7] 10.748230 10.441819  8.235895  9.230239  9.990201  7.530567
[13] 10.285544 11.202872  7.940989 10.076604  8.784941  7.859567
[19]  9.521232  8.795141 10.998430  9.794178 10.739007 10.648204
[25] 10.251162…</description>
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