Manuals/calci/CONFIDENCE

CONFIDENCE(a,sd,s)

• $a$ is alpha value which is indicating the significance level.
• $sd$ is the standard deviation.
• $s$ is the size of the sample.

Description

• This function gives value of the confidence intervals.
• Confidence intervals are calculated based on the standard error of a measurement.
• It is measures the probability that a population parameter will fall between lower bound and upper bound of the values.
• There are four steps to constructing a confidence interval.

   1. Identify a sample statistic.
   2. Select a confidence level. 
   3. Find the margin of error.
   4. Specify the confidence interval. 

• Normally once standard error value is calculated, the confidence interval is determined by multiplying the standard error by a constant that reflects the level of significance desired, based on the normal distribution.
• In $CONFIDENCE(a,sd,s)$ , $a$ is the alpha value which is indicating the significance level used to find the value of the confidence level.
• It equals $100*(1-alpha)\%$, or alpha of 0.05 indicates a 95 percent confidence level.
• This value is $\pm {1.96}$.
• $sd$ is the standard deviation of the population for the data range.
• $s$ is the size of the sample.
• Confidence interval is calculated using the following formula:

    $Confidenceinterval=samplestatistic+Marginoferror$. 

• So $confidenceinterval={\bar {x}}\pm {1.96}({\frac {\sigma }{\sqrt {s}}})$
• where ${\bar {x}}$ is the sample mean,sigma is the standard deviation.
• This function will give the result as error when

 1. Any one of the argument is nonnumeric. 
 2.Suppose $0\leq alpha\leq 1$
 3. value of s is less than 1.

• Suppose with the population of 10 for the standard deviation 3.2, with the alpha value 0.2 then, CONFIDENCE(0.2,3.2,10) =1.296839.
• So the Confidence interval value is $10\pm 1.296839=approximately[11.29,8.70]$.

CONFIDENCE (alpha, SD, n)

Where alpha is the significance level, SD is the population standard deviation for the data range and N is the sample size.

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 This function returns a value that can be use to construct a confidence interval for a population mean.

 

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·        CONFIDENCE returns the error value, when any argument is nonnumeric or alpha is less than or equal to 0 or grater than equal to 1.

·        CONFIDENCE returns the error value when SD is less than or equal to 0 or n is less than 1.

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CONFIDENCE

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Syntax

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Remarks

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Examples

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Description

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	Column1	Column2	Column3	Column4
Row1	0.05	0.993883
Row2	3
Row3	35
Row4
Row5				0
Row6
Row7

File:Calci1.gif

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AVEDEV (N1, N2...) Where N1, N 2 ...   are positive integers.

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Let’s see an example

CONFIDENCE (alpha, SD, n)

 

i.e. =CONFIDENCE (B2, B3, B4) is 0.9939

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