An indusulai plant wants to determine which of two types of fuel, electric or gas, is more cost efficient (measured in cost per unit of energy). Independent random samples were taken of plants using...

Extracted text: An indusulai plant wants to determine which of two types of fuel, electric or gas, is more cost efficient (measured in cost per unit of energy). Independent random samples were taken of plants using electricity and plants using gas. These samples consisted of 13 plants using electricity, which had a mean cost per unit of $43.98 and standard deviation of $7.94, and 8 plants using gas, which had a mean of $52.70 and standard deviation of $8.51. Assume that the populations of costs per unit are normally distributed for each type of fuel, and assume that the variances of these populations are equal. Can we conclude, at the 0.05 level of significance, that the mean cost per unit for plants using electricity, u1, is less than the mean cost per unit for plants using gas, u,? Perform a one-tailed test. Then complete the parts below. Carry your intermediate computations to three or more decimal places. (If necessary, consult a list of formulas.) (a) State the null hypothesis H, and the alternative hypothesis H,. Họ : 0 H, :0 (b) Determine the type of test statistic to use. (Choose one) ▼ (c) Find the value of the test statistic. (Round to three or more decimal places.) (d) Find the critical value at the 0.05 level of significance. (Round to three or more decimal places.) (e) Can we conclude that the mean cost per unit for plants using electricity is less than the mean cost per unit for plants using gas? Ves No