# CONFIDENCE

The `CONFIDENCE` function calculates the confidence value for a population mean. This is often used in statistical analysis to determine the range in which a population mean is likely to fall. The function takes three parameters: the significance level (alpha), the standard deviation of the population (standard_deviation), and the size of the population (pop_size).

## Usage

Use the `CONFIDENCE` formula with the syntax shown below, it has 3 required parameters:

Parameters:
1. alpha (required):
The significance level of the confidence interval. Must be between 0 and 1.
2. standard_deviation (required):
The standard deviation of the population.
3. pop_size (required):
The size of the population.

## Examples

Here are a few example use cases that explain how to use the `CONFIDENCE` formula in Google Sheets.

### Calculating the confidence interval for a population mean

Suppose you want to determine the range in which the mean height of all adults in a population falls. You can use the `CONFIDENCE` function to calculate the confidence interval at a given level of significance.

### Estimating the sample size required for a given margin of error

You can also use the `CONFIDENCE` function to estimate the sample size required to achieve a certain margin of error at a given level of significance and standard deviation.

## Common Mistakes

`CONFIDENCE` not working? Here are some common mistakes people make when using the `CONFIDENCE` Google Sheets Formula:

### Incorrect alpha value

One common mistake is providing an alpha value outside the range of 0 to 1. The alpha value represents the significance level, or the probability of observing a sample mean as extreme as the one calculated from the sample data, assuming the null hypothesis is true. Make sure the alpha value is between 0 and 1.

### Using the wrong standard deviation

Another mistake is using the wrong standard deviation. If the sample size is less than 30, use the sample standard deviation. If the sample size is 30 or greater, use the population standard deviation. Make sure you are using the correct standard deviation for your calculation.

### Incorrect population size

If the population size is known, it should be used in the formula. If the population size is unknown, the sample size should be used instead. Make sure you are using the correct population size or sample size for your calculation.

The following functions are similar to `CONFIDENCE` or are often used with it in a formula:

• `STDEV`

The `STDEV` function calculates the standard deviation of a set of numbers. It measures the amount of variation or dispersion of a set of values from the average (mean) value. It is commonly used in statistics to determine the spread of a data set. The values can be supplied as individual cells, ranges, or constants.

• `TTEST`

The `TTEST` formula is a statistical formula used to determine the probability of two sample means being equal. It is commonly used in hypothesis testing to determine if there is a significant difference between two sets of data. The formula returns the probability value associated with a t-test, which can be used to determine if the null hypothesis should be rejected or not.

• `AVERAGE`

The AVERAGE function calculates the average (arithmetic mean) of the values passed to it. It is commonly used to find the average of a range of cells containing numerical data.

• `VAR`

The `VAR` formula calculates the variance of a set of numerical values. Variance is a measure of how spread out a set of data is in relation to the mean. This formula is commonly used in statistical analysis to measure the variability or diversity of a dataset.

You can learn more about the `CONFIDENCE` Google Sheets function on Google Support.