# Resolved: T- score used in the solution is for alpa, not divided by 2. Why

Please am confused with how to check the t-score table. The video shows that you divide the alpha by 2 e.g alpha is 0.05, divide by 2 which gives 0.025.

We are supposed to check 0.025 against the degree of freedom, to get the intersect.

But solution keeps using the alpha figure(without dividing it by 2).

Please I need clarification.

Hi,

Which solution?

in the exercise solution file, t-statistics for alpha (0.05/2) or (alpha 0.025) is correct -> 2.26.

Hi there, a 95% CI suggests that we need to capture 95% of data inbetween 2 points. Therefor we need 2.5% of the data to the left of the lower point, 95% of data within the two points and 2.5% of data above the higher point. This is why for a 2 tail test we need to consider alpha/2. If this was a 1-tail test then this suggests there is a strict known value for a lower bound like 0 of +/- infinite, therefor we would want to have 95% data below the upper value and 5% data above this value for a 95% CI.