The Google Sheets function CONFIDENCE.NORM is a statistical tool used to determine the margin of error for a given confidence interval in the context of a normal distribution. This function is particularly useful for researchers, data analysts, and anyone involved in statistical analysis, as it allows for more informed decision-making based on the accuracy of sample data.

Syntax

CONFIDENCE.NORM(alpha, standard_dev, size)

• alpha: The significance level, which indicates the probability that the confidence interval does not contain the true population mean.
• standard_dev: The standard deviation of the population, which reflects the degree of variation in the data.
• size: The size of the sample, representing the number of observations used for computation.

Example #1

CONFIDENCE.NORM(0.05, 10, 30)

This function calculates the margin of error for a 95% confidence level, with a standard deviation of 10 and a sample size of 30. The result would be approximately 3.65.

Example #2

CONFIDENCE.NORM(0.01, 5, 50)

Here, the function computes the margin of error for a 99% confidence interval, given a standard deviation of 5 and a sample size of 50. The result is around 1.18.

Example #3

CONFIDENCE.NORM(0.10, 8, 20)

In this case, the function determines the margin of error for a 90% confidence level, with a standard deviation of 8 and a sample size of 20. The output is approximately 2.74.

Error handling

• NUM! Occurs if the alpha is not between 0 and 1, or if the size is less than 1.
• DIV/0! This error is displayed if the standard_dev is zero.
• VALUE! Indicates that the inputs are of the wrong type. Ensure that numerical values are provided where required.

Conclusion

The CONFIDENCE.NORM function in Google Sheets is an essential tool for anyone looking to perform statistical analysis based on sample data. By providing a clear method to calculate the margin of error, users can better understand the reliability of their estimates and make more informed conclusions in their respective fields.