Answer:
The critical value is
Step-by-step explanation:
From the question we are told that
The sample size is n = 15
The level of significance is
The null hypothesis is
The alternative hypothesis is
Here is average time for previous year
is the average time for current year
Generally the degree of freedom is mathematically represented as
=>
=>
Generally from the student t distribution table the critical value for at a degree of freedom of for a two tailed test is