Question

the p value of a t test equal to 1.25 with 30 degrees of freedom is ?

Answer 1

Solution:-

We have given that,

The t-test statistics value is,

t-statistic = t* = 1.25

And degrees of freedom for the test is n=30

Now,we have to find p_value for t-statistics as follows.

Case 1)

If the test is one tailed ( left sided), then the p_value is given as

p_value = Probability ( t < t*) with "n" degrees of freedom

p_value = Probability ( t < 1.25) with "30" degrees of freedom

p_value = 0.889518

Case 2)

If the test is one tailed (right sided), then the p_value is given as

p_value = Probability ( t > t *) with "n" degrees of freedom

p_value = Probability ( t > 1.25) with "30" degrees of freedom

p_value = 0.110482

Case 3)

If the test is two tailed (two sided), then the p_value is given as

p_value = 2*Probability ( t > | t *|) with "n" degrees of freedom

Where,. | t* | = absolute value of t*  

p_value = 2*Probability ( t > |1.25|) with "30" degrees of freedom

p_value = 0.220964

Result:-

T-test	t-statistics	deg.of freedom	p_values
Left tailed	1.25	30	0.889518
Right tailed	1.25	30	0.110482
Two tailed	1.25	30	0.220964