Answer:
a) [tex] t_{\alpha}= 1.753[/tex]
b) [tex] t_{\alpha}= -1.383[/tex]
c) [tex] t_{\alpha/2}= \pm 2.179[/tex]
Step-by-step explanation:
Part a
For this case we know that the degrees of freedom are:
[tex] df = 15[/tex]
And we want a right tailed test so then we need to find in the t distribution with degrees of freedom =15 a critical value who accumulate 0.05 of the area in the right and we got:
[tex] t_{\alpha}= 1.753[/tex]
Part b
For this case the significance is [tex]\alpha=0.1[/tex] the degrees of freedom are:
[tex] df = n-1= 10-1=9[/tex]
And since is a left tailed test the critical value for this case would be:
[tex] t_{\alpha}= -1.383[/tex]
Part c
For this case the significance is [tex]\alpha=0.05[/tex] and [tex]\alpha/2=0.025[/tex] the degrees of freedom are:
[tex] df = n-1= 13-1=12[/tex]
And since is a two tailed test the critical values for this case would be:
[tex] t_{\alpha/2}= \pm 2.179[/tex]
