The аverаge lifetime оf circulаted $1 bills is 18 mоnths. A researcher believe that the average lifetime is nоt 18 months. He researched the lifetime of 48 $1 bills and found the average lifetime was 18.8, with a sample standard deviation of 2.8 months. At α = 0 . 05 , can it be concluded that the average lifetime of a circulated $1 bill differs from 18 months? State the Hypotheses Null H 0 : μ = [BLANK-1] Alternative H A : μ ≠ [BLANK-2] Find the critical value This is a [BLANK-3]-tailed test with α = 0 . 05 . Since we do not know the population proportion, we can must use the [BLANK-4] distribution. With n = [BLANK-5], we calculate the degrees of freedom to be [BLANK-6]. This isn't on the chart so we can use 45 instead. t C V = [BLANK-7] Compute the test statistic x = [BLANK-8] s = 2 . 8 t = x - μ s n = [BLANK-9] (two decimal places) Make a decision Because the test statistic is (inside/outside) [BLANK-10] the rejection region, we should (reject/ fail to reject) [BLANK-11] the null hypothesis. There (is/is no) [BLANK-12] evidence that the average lifetime of a circulated $1 bill differs from 18 months.