Answer:
The critical value is [tex]t_{\frac{0.10}{2} , 14 } =[ - 1.761,1.761][/tex]
Step-by-step explanation:
From the question we are told that
The sample size is n = 15
The level of significance is [tex]\alpha = 0.10[/tex]
The null hypothesis is [tex]H_o : \mu _1 = \mu_2[/tex]
The alternative hypothesis is [tex]H_a : \mu_1 \ne \mu_2[/tex]
Here [tex]\mu_1[/tex] is average time for previous year
[tex]\mu_2[/tex] is the average time for current year
Generally the degree of freedom is mathematically represented as
[tex]df = n -1[/tex]
=> [tex]df = 15 - 1[/tex]
=> [tex]df = 14[/tex]
Generally from the student t distribution table the critical value for [tex]\frac{\alpha }{2}[/tex] at a degree of freedom of [tex]df = 14[/tex] for a two tailed test is
[tex]t_{\frac{0.10}{2} , 14 } =[ - 1.761,1.761][/tex]