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.


  • 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.


  1. Example 1
1 10 15 7 2 19 20 12
2 3 4 8 1 10 15 5
  1. =ZTEST(A1:G1,4) = 0.00042944272036
  2. =2*MIN(ZTEST(A1:G1,4),1-ZTEST(A1:G1,4)) = 0.000858885440
  3. =ZTEST(A2:F2,10) = 0.9708451547030459
  4. =2*MIN(ZTEST(A2:F2,10),1-ZTEST(A2:F2,10)) = 0.058309690593908226

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