If the absolute value of your calculated t-statistic exceeds the critical value from the standard normal distribution, you can reject the null hypothesis . Set the significance level, α, the probability of making a Type I error to be small 0.01, 0.05, or 0.10. Compare the P-value to α. If the P-value is less than (or equal to) α, reject the null hypothesis in favor of the alternative hypothesis. If the P-value is greater than α, do not reject the null hypothesis.