# Manuals/calci/ZTEST

**ZTEST (Array,Mean,StandardDeviationForPopulation,IsTwoTailed,Accuracy)**

- is the set of values.
- is the mean value.
- is the standard deviation of the population.
- is the value of the tail.
- gives accurate value of the solution.
- ZTEST() returns the one-tailed probability-value of a z-test.

## Description

- This function gives the one-tailed probability of z-test.
- Z-test is used to determine whether two population means are different when the variances are known and the sample size is large.
- In , is the array of values against which the hypothesized sample mean is to be tested.
- is the hypothesized sample mean, and is the standard deviation of the population.
- When we are not giving the sigma value, it will use the standard deviation of sample.
- This function returns the probability that the supplied hypothesized sample mean is greater than the mean of the supplied data values.
- The test statistic should follow a normal distribution.
- ZTEST is calculated when sigma is not omitted and x=μ0 :
- ZTEST is calculated when sigma is omitted and x=μ0:

where is sample mean , is the sample deviation and is the size of the sample.

- Suppose we want to calculate the z-test for two tailed probability then this can be done by using the Z_test function: .
- This function will give the result as error when

1. Any one of the argument is non-numeric. 2. Array or Mean value is empty. 3. Array contains only one value.

## Examples

**Example 1**

A | B | C | D | E | F | G | |
---|---|---|---|---|---|---|---|

1 | 10 | 15 | 7 | 2 | 19 | 20 | 12 |

2 | 3 | 4 | 8 | 1 | 10 | 15 | 5 |

- =ZTEST(A1:G1,4) = 0.00042944272036
- =2*MIN(ZTEST(A1:G1,4),1-ZTEST(A1:G1,4)) = 0.000858885440
- =ZTEST(A2:F2,10) = 0.9708451547030459
- =2*MIN(ZTEST(A2:F2,10),1-ZTEST(A2:F2,10)) = 0.058309690593908226

## Related Videos

## See Also

## References