Difference between revisions of "TMean2Estimate Command"

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;TMean2Estimate[<Sample Mean 1 >,<Sample Standard Deviation 1 >, <Sample Size 1>, <Sample Mean 2 >,<Sample Standard Deviation 2 >, <Sample Size 2>, <Level>,<Boolean Pooled>]
 
;TMean2Estimate[<Sample Mean 1 >,<Sample Standard Deviation 1 >, <Sample Size 1>, <Sample Mean 2 >,<Sample Standard Deviation 2 >, <Sample Size 2>, <Level>,<Boolean Pooled>]
: Calculates a T confidence interval estimate of the difference between two population means using the given sample statistics and confidence ''Level''. Results are returned in list form as {lower confidence limit,  upper confidence limit}.  
+
: Calculates a T confidence interval estimate of the difference between two population means using the given sample statistics and confidence ''Level''. ''Pooled'' is defined as above. Results are returned in list form as {lower confidence limit,  upper confidence limit}.
:''Pooled'' is defined as above.
 
 
 
{{Note| 1= This interval has definition:  '''''(sample mean1 - sample mean2) ± t* SE''''', where
 
:: n1, n2 = sample sizes
 
:: s1, s2 = sample standard deviations
 
:: If pooled = true
 
::: sp = [http://en.wikipedia.org/wiki/Pooled_variance pooled standard deviation]
 
::: SE = sp * sqrt(1/n1 + 1/n2)
 
::: t* =  critical value for given confidence ''Level'' and T distribution with degrees of freedom = n1 + n2 - 2.
 
 
 
:: If pooled = false
 
::: SE = sqrt(s1^2/n1 + s2^2/n2)
 
::: t* =  critical value for given confidence ''Level'' and T distribution with degrees of freedom given by the    [http://en.wikipedia.org/wiki/Welch%27s_t_test Welch-Satterthwaite approximation] .
 
}}
 

Revision as of 04:59, 23 July 2011



TMean2Estimate[<List of Sample Data 1>,<List of Sample Data 2>,<Level>,<Boolean Pooled>]
Calculates a T confidence interval estimate of the difference between two population means using the given sample data sets and confidence Level.
If Pooled = true, then population variances are assumed equal and sample standard deviations are combined in calculation.
If Pooled = false, then population variances are not assumed equal and sample standard deviations are not combined.
Results are returned in list form as {lower confidence limit, upper confidence limit}.
TMean2Estimate[<Sample Mean 1 >,<Sample Standard Deviation 1 >, <Sample Size 1>, <Sample Mean 2 >,<Sample Standard Deviation 2 >, <Sample Size 2>, <Level>,<Boolean Pooled>]
Calculates a T confidence interval estimate of the difference between two population means using the given sample statistics and confidence Level. Pooled is defined as above. Results are returned in list form as {lower confidence limit, upper confidence limit}.
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