An industrial 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 14 plants using electricity, which had a mean cost per unit of $49.2 and standard deviation of $8.55, and 10 plants using gas, which had a mean of $50.1 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 0.1 level of significance, that the means cost per unit for plants using electricity, mu1, is less than the mean cost per unit for plants using gas, mu2? Perform a one tailed test. Then fill in the table below.
The solution provides step by step method for the calculation of one sample t test . Formula for the calculation and Interpretations of the results are also included.