Right-tailed test
A right-tailed test is used when the alternative hypothesis states that the true value of the parameter specified in the null hypothesis is greater than the null hypothesis claims.
Suppose that we want to determine the Z critical value for a right-tailed test having a significance level equal to 0.01 bypassing the p-value to 0.01 and the lower.tail to false due to the right-tailed test of the qnorm function in the R.
R
# Determine the Z critical value qnorm(p=.01, lower.tail=FALSE) |
Output:
Right-tailed test:
Interpretation of output:
The Z critical values come out to be equal to 2.326. Therefore, if the test statistics comes out to be greater than this value then the outcome of the hypothesis test would be considered statistically significant.
How to Find Z Critical Values in R
When we conduct a hypothesis test, we obtain test statistics as an outcome. Now in order to find out whether the outcome of the hypothesis test is statistically significant, the Z critical value is compared with the test statistic. If the absolute value of the test statistic comes out to be greater than the Z critical value then the outcome of the hypothesis test is considered statistically significant.