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Author's title

Author*The author of this computation has been verified*
R Software Modulerwasp_hypothesisvariance3.wasp
Title produced by softwareTesting Variance - Confidence Intervals for Sample Variance
Date of computationFri, 07 Nov 2008 06:11:06 -0700
Cite this page as followsStatistical Computations at FreeStatistics.org, Office for Research Development and Education, URL https://freestatistics.org/blog/index.php?v=date/2008/Nov/07/t1226063531alwqsvt0pwvruix.htm/, Retrieved Sun, 19 May 2024 04:52:12 +0000
Statistical Computations at FreeStatistics.org, Office for Research Development and Education, URL https://freestatistics.org/blog/index.php?pk=22488, Retrieved Sun, 19 May 2024 04:52:12 +0000
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Original text written by user:
IsPrivate?No (this computation is public)
User-defined keywords
Estimated Impact210

Tree of Dependent Computations

Family? (F = Feedback message, R = changed R code, M = changed R Module, P = changed Parameters, D = changed Data)
F       [Testing Variance - Confidence Intervals for Sample Variance] [] [2008-11-07 13:11:06] [7596afe9a05f2a2719ece78b1b0e12e6] [Current]
Feedback Forum
2008-11-17 11:21:02 [Nicolaj Wuyts] [reply] 
Hier gebruik je: testing mean with known variance - Sample size. De population variance is 0,012; de nul hypothese is 0,15;de alternatieve nul hypothese is 0,152; de type I error is 0,05 en de type II error is ook 0,005. Aangezien we 95 procent van de gevallen willen detecteren moeten we 100%-95% doen, wat gelijk is aan 5%. Door deze bewerking krijg je een sample size van 32467, wat veel te groot is om realistisch te zijn. Het percentage van 95% is dus niet haalbaar.
2008-11-17 11:29:02 [Nicolaj Wuyts] [reply] 
Excuses voor mijn vorige post. Deze hoorde eigenlijk bij vraag vier. Hier volgt de commentaar op vraag 5:
Hier gebruik je: Testing population mean with known variance - Confidence interval. De populatie variantie is 0,012; De steekproefgrootte is 27, de steekproefmediaan is 0,1546 en het confidence interval is 0,95. We moeten hier kijken naar de one-tailed hypothese omdat we hier nog steeds spreken over een te veel aan vet in het vlees. Als we dan kijken naar het interval dat berekent wordt voor de one-tailed hypothese, zien we dat het interval loopt van 0.119923440808296 tot 0.189276559191704. Het steekproefgemiddelde behoort hier uiteraard toe.
2008-11-24 16:31:44 [4679c4d03f1d346a85e79d87ba60ec2b] [reply] 
Verkeerde methode met wederom verkeerde gegevens. De methode zou testing population mean with known variance-confidence interval moeten zijn. De gegevens hebben dezelfde fouten als de vorige vragen. Hier zou je gebruik moeten maken van de one-sided test van de rechterkant omdat enkel de afwijking van het vetpercentage naar boven toe een voordeel oplevert. De sample mean van 0.1546 ligt onder de waarde van de rechterkant nl 0.189276559191704. Je kunt dus stellen dat deze binnen de betrouwbaarheidsinterval ligt.

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Dataset

Tables (Output of Computation)





Summary of computational transaction
Raw Inputview raw input (R code)
Raw Outputview raw output of R engine
Computing time2 seconds
R Server'Herman Ole Andreas Wold' @ 193.190.124.10:1001

\begin{tabular}{lllllllll}
\hline
Summary of computational transaction \tabularnewline
Raw Input & view raw input (R code)  \tabularnewline
Raw Output & view raw output of R engine  \tabularnewline
Computing time & 2 seconds \tabularnewline
R Server & 'Herman Ole Andreas Wold' @ 193.190.124.10:1001 \tabularnewline
\hline
\end{tabular}
%Source: https://freestatistics.org/blog/index.php?pk=22488&T=0

[TABLE]
[ROW][C]Summary of computational transaction[/C][/ROW]
[ROW][C]Raw Input[/C][C]view raw input (R code) [/C][/ROW]
[ROW][C]Raw Output[/C][C]view raw output of R engine [/C][/ROW]
[ROW][C]Computing time[/C][C]2 seconds[/C][/ROW]
[ROW][C]R Server[/C][C]'Herman Ole Andreas Wold' @ 193.190.124.10:1001[/C][/ROW]
[/TABLE]
Source: https://freestatistics.org/blog/index.php?pk=22488&T=0

Globally Unique Identifier (entire table): ba.freestatistics.org/blog/index.php?pk=22488&T=0

As an alternative you can also use a QR Code:  
QR Code


The GUIDs for individual cells are displayed in the table below:

Summary of computational transaction
Raw Inputview raw input (R code)
Raw Outputview raw output of R engine
Computing time2 seconds
R Server'Herman Ole Andreas Wold' @ 193.190.124.10:1001






Testing Variance - Confidence Intervals for Sample Variance
Sample size27
Null hypothesis (H0)15
Confidence interval0.95
Type of IntervalLeft tailRight tail
Two-sided confidence interval at 0.957.9868682588505424.186444286358
Left one-sided confidence interval at 0.958.87259033649716+inf
Right one-sided confidence interval at 0.95022.4337338422096
more information about confidence interval

\begin{tabular}{lllllllll}
\hline
Testing Variance - Confidence Intervals for Sample Variance \tabularnewline
Sample size & 27 \tabularnewline
Null hypothesis (H0) & 15 \tabularnewline
Confidence interval & 0.95 \tabularnewline
Type of Interval & Left tail & Right tail \tabularnewline
Two-sided confidence interval at  0.95 & 7.98686825885054 & 24.186444286358 \tabularnewline
Left one-sided confidence interval at  0.95 & 8.87259033649716 & +inf \tabularnewline
Right one-sided confidence interval at  0.95 & 0 & 22.4337338422096 \tabularnewline
more information about confidence interval \tabularnewline
\hline
\end{tabular}
%Source: https://freestatistics.org/blog/index.php?pk=22488&T=1

[TABLE]
[ROW][C]Testing Variance - Confidence Intervals for Sample Variance[/C][/ROW]
[ROW][C]Sample size[/C][C]27[/C][/ROW]
[ROW][C]Null hypothesis (H0)[/C][C]15[/C][/ROW]
[ROW][C]Confidence interval[/C][C]0.95[/C][/ROW]
[ROW][C]Type of Interval[/C][C]Left tail[/C][C]Right tail[/C][/ROW]
[ROW][C]Two-sided confidence interval at  0.95[/C][C]7.98686825885054[/C][C]24.186444286358[/C][/ROW]
[ROW][C]Left one-sided confidence interval at  0.95[/C][C]8.87259033649716[/C][C]+inf[/C][/ROW]
[ROW][C]Right one-sided confidence interval at  0.95[/C][C]0[/C][C]22.4337338422096[/C][/ROW]
[ROW][C]more information about confidence interval[/C][/ROW]
[/TABLE]
Source: https://freestatistics.org/blog/index.php?pk=22488&T=1

Globally Unique Identifier (entire table): ba.freestatistics.org/blog/index.php?pk=22488&T=1

As an alternative you can also use a QR Code:  
QR Code


The GUIDs for individual cells are displayed in the table below:

Testing Variance - Confidence Intervals for Sample Variance
Sample size27
Null hypothesis (H0)15
Confidence interval0.95
Type of IntervalLeft tailRight tail
Two-sided confidence interval at 0.957.9868682588505424.186444286358
Left one-sided confidence interval at 0.958.87259033649716+inf
Right one-sided confidence interval at 0.95022.4337338422096
more information about confidence interval


Figures (Output of Computation)

Input Parameters & R Code

Parameters (Session):
par1 = 27 ; par2 = 15 ; par3 = 0.95 ;
Parameters (R input):
par1 = 27 ; par2 = 15 ; par3 = 0.95 ;
R code (references can be found in the software module):
par1<-as.numeric(par1)
par2<-as.numeric(par2)
par3<-as.numeric(par3)
df <- par1 - 1
halfalpha <- (1 - par3) / 2
ua <- qchisq(halfalpha,df) * par2 / df
ub <- qchisq(1-halfalpha,df) * par2 / df
ua
ub
ul <- qchisq(1-par3,df) * par2 / df
ul
ur <- qchisq(par3,df) * par2 / df
ur
load(file='createtable')
a<-table.start()
a<-table.row.start(a)
a<-table.element(a,hyperlink('ht_variance.htm','Testing Variance - Confidence Intervals for Sample Variance','learn more about Statistical Hypothesis Testing about the Variance'),3,TRUE)
a<-table.row.end(a)
a<-table.row.start(a)
a<-table.element(a,'Sample size',header=TRUE)
a<-table.element(a,par1,2)
a<-table.row.end(a)
a<-table.row.start(a)
a<-table.element(a,'Null hypothesis (H0)',header=TRUE)
a<-table.element(a,par2,2)
a<-table.row.end(a)
a<-table.row.start(a)
a<-table.element(a,'Confidence interval',header=TRUE)
a<-table.element(a,par3,2)
a<-table.row.end(a)
a<-table.row.start(a)
a<-table.element(a,'Type of Interval',header=TRUE)
a<-table.element(a,'Left tail',header=TRUE)
a<-table.element(a,'Right tail',header=TRUE)
a<-table.row.end(a)
a<-table.row.start(a)
a<-table.element(a,paste('Two-sided confidence interval at ',par3), header=TRUE)
a<-table.element(a,ua)
a<-table.element(a,ub)
a<-table.row.end(a)
a<-table.row.start(a)
a<-table.element(a,paste('Left one-sided confidence interval at ',par3), header=TRUE)
a<-table.element(a,ul)
a<-table.element(a,'+inf')
a<-table.row.end(a)
a<-table.row.start(a)
a<-table.element(a,paste('Right one-sided confidence interval at ',par3), header=TRUE)
a<-table.element(a,'0')
a<-table.element(a,ur)
a<-table.row.end(a)
a<-table.row.start(a)
a<-table.element(a, hyperlink('ht_variance.htm#ex3', 'more information about confidence interval','example'),3,TRUE)
a<-table.row.end(a)
a<-table.end(a)
table.save(a,file='mytable.tab')