**Method 1 – CONFIDENCE Function**

It returns the confidence value for the population mean using the normal distribution. The syntax for this function is.

**CONFIDENCE(alpha,standard_dev,size)**

Alpha is the level of significance. The value for **alpha** must be **0** < **alpha** < **1**, **standard_dev** refers to the standard deviation for the population. **Size** refers to sample size.

**Method 2 – CONFIDENCE.NORM Function**

This function calculates the confidence interval for a population mean using a normal distribution. The syntax of this function is.

**CONFIDENCE.NORM(alpha,standard_dev,size)**

Alpha is the level of significance. The value for **alpha** must be **0** < **alpha** < **1**, **standard_dev** refers to the standard deviation for the population. **Size** refers to sample size.

**Method 3 – CONFIDENCE.T Function**

It returns the confidence interval for a population mean and uses a Student’s t distribution. The syntax for this function is.

**CONFIDENCE.T(alpha,standard_dev,size)**

Alpha is the level of significance. The value for **alpha** must be **0** < **alpha** < **1**, **standard_dev** refers to the standard deviation for the population. **Size** refers to sample size.

## How to Calculate Confidence Interval in Excel

### Method 1 – Use Generic Formula to Calculate Confidence Interval in Excel

- Select the cell where you want the
**Mean**>> Write the following formula.

`=AVERAGE(C5:C12)`

- Press
**Enter**.

- Select the cell where you want the
**Standard Deviation**(we wanted the result for sample standard deviation) >> Write the following formula.

`=STDEV.S(C5:C12)`

- Press
**Enter**.

- Select the cell where you want the
**Sample Size**>> Write the following formula.

`=COUNTA(B5:B12)`

- Press
**Enter**.

- Select the cell where you want the
**Z Score**>> Write the**Z Score**for your**Confidence Level**.

**Here, my**

*Note:***Confidence Level**is

**95%**and the

**Z Score**for that is

**1.96**. You have to change that according to your confidence level.

- Select the cell where you want the
**Confidence Value**>> Write the following formula.

`=C17*(C15/SQRT(C16))`

- Press
**Enter**.

- Select the cell where you want the
**Confidence Interval**>> Write the following formula.

`=TEXT(C14,"#,##0.00")&" ± "&TEXT(C18,"#,##0.00")`

- Press
**Enter**.

**How Does the Formula Work?**

**TEXT(C14,”#,##0.00″):**Here,**the TEXT function**changes the value format in cell**C14**to a thousand separator with**2**decimal points.**TEXT(C14,”#,##0.00″)&” ± “&TEXT(C18,”#,##0.00”):**The**Ampersand Operator (&)**joins these formulas with the “**±**” sign.

### Method 2 – Apply Excel CONFIDENCE Function to Calculate Confidence Interval

- Calculate the
**Mean**like the previous method.

- Select the cell where you want the
**Standard Deviation**(here, I wanted the result for population standard deviation) >> Write the following formula.

`=STDEV.P(C5:C12)`

- Press
**Enter**.

- Calculate the
**Sample Size**like the previous method.

- Select the cell where you want the
**Level of Significance**>> Write the following formula.

`=1-0.95`

- Press
**Enter**.

*The Confidence Level is*

**Note:****95%**. For that reason, I used

**0.95**. You will have to change this

**Value**accordingly.

- Select the cell where you want the
**Confidence Value**>> Write the following formula.

`=CONFIDENCE(C17,C15,C16)`

- Press
**Enter**.

- Select the cell where you want the
**Confidence Interval**>> Write the following formula.

`=TEXT(C14,"#,##0.00")&" ± "&TEXT(C18,"#,##0.00")`

- Press
**Enter**.

### Method 3 – Calculate Confidence Interval Using Excel CONFIDENCE.NORM Function

- Find
**Mean**,**Standard Deviation**,**Sample Size**, and**Level of Significance**like the previous method.

- Select the cell where you want the
**Confidence Value**>> Write the following formula.

`=CONFIDENCE.NORM(C17,C15,C16)`

- Press
**Enter**.

- Select the cell where you want the
**Confidence Interval**>> Write the following formula.

`=TEXT(C14,"#,##0.00")&" ± "&TEXT(C18,"#,##0.00")`

- Press
**Enter**.

### Method 4 – Use CONFIDENCE.T Function to Calculate Confidence Interval

- Find
**Mean**,**Standard Deviation**,**Sample Size**, and**Level of Significance**like the previous method.

- Select the cell where you want the
**Confidence Value**>> Write the following formula.

`=CONFIDENCE.T(C17,C15,C16)`

- Press
**Enter**.

- Select the cell where you want the
**Confidence Interval**>> Write the following formula.

`=TEXT(C14,"#,##0.00")&" ± "&TEXT(C18,"#,##0.00")`

- Press
**Enter**.

### Method 5 – Apply Data Analysis Feature to Calculate Confidence Interval

- Go to the
**File**tab.

- Select
**Options**.

- Select
**Add-ins**tab >>**Go**from**Manage**.

**Add-ins**dialog box appears >> check**Analysis ToolPak**>> check**Solver Add-in**>> select**OK**.

- Go to the
**Data**tab >> select**Data Analysis**.

**Data Analysis**dialog box appears >> Select**Descriptive Statistics**>> select**OK**.

- A
**Descriptive Statistics**dialog box will appear. - Select Input
**Range**>> check**Labels in the first row**if your range contains**Labels**>> select**Output Range**>> check**Summary****statistics**>> check**Confidence Level for Mean**and write the**Confidence Level**>> select**OK**.

- You will see a summary with the
**Confidence Value**.

## Things to Remember

- You have to remember that
**CONFIDENCE**functions only take numeric values. - You must use the correct function for calculating
**Standard Deviation**.

## Frequently Asked Questions

**1. How do you find the 95 percent confidence interval?**

To find the **95 **percent confidence interval you will have to set **alpha** as **(1-0.95)** in the **CONFIDENT **function.

**2. How to calculate Sample Size?**

You can use **the COUNTA function** to calculate the **Sample Size**.

**3. How to find the upper and lower limits of a confidence interval?**

For the upper limit, you will have to **add **the **Confidence Value **with the **Mean**. And for the lower limit, you will have to **subtract **the **Confidence Value **from the **Mean**.

**Download Practice Workbook**

You can download the practice workbook from here.

## Confidence Interval in Excel: Knowledge Hub

**Calculate Confidence Interval****Make Confidence Interval Graph****Find Upper and Lower Limits of Confidence Interval****Find Confidence Interval for Two Samples****Confidence Interval for Difference in Means****Calculate Confidence Interval for Population Mean****Find Confidence Interval Proportion****Calculate 95 Percent Confidence Interval****Determine 99 Percent Confidence Interval****Linear Regression Confidence Interval****Calculate Z-Score with 95 Confidence Interval****Find P-Value from Confidence Interval**

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