How to Calculate Confidence Interval Without Standard Deviation in Excel

The article will show you how to calculate Confidence Interval without standard deviation in Excel. Basically, it’s easy to determine the Confidence Interval when the Standard Deviation is known but in some aspects, the Standard Deviation is not derived for this purpose. I’ll show you some easy and effective methods on how to calculate the Confidence Interval without the Standard Deviation in this article.

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What Is Confidence Interval?

A Confidence Interval (CI) is a range of estimates for an unknown population characteristic or parameter in frequentist statistics. The 95% Confidence level is the most popular, however other levels, such as 90% or 99%, are occasionally used when computing Confidence Intervals. The percentage of related CIs over the long run that includes the parameter’s actual value is represented by the Confidence level. For instance, 95% of all intervals calculated at the 95% Confidence level should include the parameter’s actual value.

The formula to calculate the Confidence Interval without the Standard Deviation is given below.

2 Ways to Calculate Confidence Interval Without Standard Deviation

Suppose, we want to analyze the download numbers of some android apps. So we have the Application Names and their number of Download times in the dataset. We are going to find out the Confidence Interval of the Downloads data without their Standard Deviation.

1. Using Excel TINV Function to Calculate Confidence Interval

As the t Value is one of the parameters to calculate the Confidence Interval, and it is also one of the vital parameters when calculating without the Standard Deviation, we have to determine this by the TINV function.

Steps:

• First, set a sample Standard Deviation and use the following formula to calculate the Average of the Download We consider the Confidence Level to be 95%. Hence the alpha will be 5% or 0.05.

The formula uses the AVERAGE function to return the mean of the data.

• Next, we will use the following formula to determine the Sample Size of the dataset.

The formula uses the COUNT function to return the number of data entries (Sample Size).

• Thereafter, we will calculate the Standard Error by the following formula.

We get the Standard Error with the help of the Sample Standard Deviation and the square root of Sample Size. It applies the SQRT function.

• Next, the t value is calculated by the TINV function.

We inserted the alpha and degrees of freedom as the arguments of the function. We have one sample here, the download data. So the degrees of freedom will be: Sample Size – 1 which is actually 10-1=9.

• After that, type the following formula to calculate the second term of the Confidence Interval This term is known as Margin of Error.

• Finally, we have all the data for calculating the Confidence Interval. Type the following formula to determine the Lower Limit of the Confidence Interval.

• The next formula will return the Upper Limit of the Confidence Interval.

Thus you can calculate Confidence Interval without standard deviation in Excel using the TINV function.

Read More: How to Calculate 95 Percent Confidence Interval in Excel (4 Ways)

2. Applying CONFIDENCE.T Function to Calculate Confidence Interval

We can also use the CONFIDENCE.T function to calculate the Confidence Interval. Let’s follow the instructions below.

Steps:

• First, we will use the following formula to calculate the Margin of Error.

• Next, write down the following formula to calculate the Average of the Download

• The next formula returns the Lower Limit of the Confidence Interval.

• And the following one returns the Upper Limit of the Confidence Interval.

Thus you can calculate Confidence Interval in Excel using the CONFIDENCE.T function.

Read More: How to Calculate 90 Percent Confidence Interval in Excel

How to Find Confidence Interval for Two Samples in Excel

In this strategy, the CONFIDENCE function will serve as the cornerstone of our plan. Alpha, Standard Deviation, and Sample Size are the required inputs for this function. As a result, it gives us the sample’s level of Confidence. It uses the normal distribution in this instance. Follow the instructions precisely to get the method. Let’s have a look at the two sample dataset below.

Steps:

• First, type the following formula in cell F4 which will return the Margin of Error.

The formula returns the Margin of Error with the help of CONFIDENCE and STDEV.S functions.

• Next, store the Average of these samples in F5.

• Finally, subtract and add the Margin of Error with the Average to get the Lower and Upper limit of the Confidence Interval

Thus you can find the Confidence Interval for two samples.

Confidence Interval Without Standard Deviation Calculator

Here, I created a sheet to calculate the Confidence Interval without the Standard Deviation. You can just insert your data and get the result automatically. You also need to insert the Sample Standard Deviation and Confidence Level of your choice.

Read More: Linear Regression Confidence Interval in Excel (Calculation and Interpretation)

Conclusion

Suffice to say, we can consider that you have learnt some effective tactics to calculate Confidence Interval without standard deviation in Excel. If you have any better suggestions or questions or feedback regarding this article, please share them in the comment box. This will help me enrich my upcoming articles. For more queries, kindly visit our website ExcelDemy.

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