Two side t statistic table
what is the difference between finding, one side and two side t-statistic values from the table. And how to find t-statistic vales for two sided distribution.
On the one sided test, the hypothesis tested is directional and you want to find out whether your mean is greater or smaller than the population parameter. On the two sided test, the hypothesis is not directional(that's why we test the positive and negative side). They are both used in different occasions.
If for example we develop a new drug and want to check how much better it does vs an existing one we would conduct a one sided test. But doing so also has it's cons since you will fail to check if it performs worse than the existing drug.
Also to find the t-stat for a 2 sided test you just divide the alpha you've got. If you do a test with 5% significance you will divide 0.05 with 2 and get 0.025 and check the t stat table to find the one you want(you also need to consider your degrees of freedom).