The following article details how to use the ZTEST function - The function to calculate the one-sided probability value of a z test.
Description: The function returns the one-sided probability value of the z test. For the hypothetical population mean, the function returns the probability that the sample mean will be greater than the sample mean observed in the data set or array.
Syntax: ZTEST (array, x, [sigma]) .
Inside:
- array : An array or range of data to test for x, which is a required parameter.
- x : Value to check, required parameters.
- sigma : The overall standard deviation, if omitted the default value is the sample standard deviation, is an arbitrary parameter.
Attention:
- If array array is empty -> the function returns the # N / A error value.
- ZTEST function is calculated based on the formula:
+ Where sigma is used:
+ In case of omitting sigma parameter:
- ZTEST function indicates that the probability that the sample mean will be greater than the observed value is AVERAGE (array) when the average of the basic population is μ0 => ZTEST will return a value greater than 0.5 when AVERAGE ( array) < μ0 .
- You can use the ZTEST function to calculate the probability of 2 sides based on the formula:
2 * MIN (ZTEST (array, μ0, sigma), 1 - ZTEST (array, μ0, sigma)) .
For example:
Step 1: In the cell to calculate enter the formula: = ZTEST (D6: I6, D7) .
Step 2: Press Enter -> ZTEST function value is:
In addition, you can also calculate the 2-sided probability based on the ZTEST function :
Step 1 : In the cell to calculate, enter the formula: = 2 * MIN (ZTEST (D6: I6, D7), 1-ZTEST (D6: I6, D7)) .
Step 2: Press Enter -> the value of the ZTEST function on both sides is:
Above is a detailed guide of meaning, usage and some notes when using ZTEST .
Good luck!