T Value And Z Value. As the data size increases distribution tends to be z distribution. For a large sample size sample variance will be a better estimate of population variance so even if population variance is unknown we can use the z test using sample variance.
Z score ranges from 3 to 3 while the t score ranges from 20 to 80. If the sample size is large enough then the z test and t test will conclude with the same results. T scores are used when the conversion is made without knowledge of the population standard deviation and mean.
T scores are used when the conversion is made without knowledge of the population standard deviation and mean.
For a large sample size sample variance will be a better estimate of population variance so even if population variance is unknown we can use the z test using sample variance. T scores are used when the conversion is made without knowledge of the population standard deviation and mean. Z score ranges from 3 to 3 while the t score ranges from 20 to 80. Z scores are based on your knowledge about the population s standard deviation and mean.
