You are interested in determining whether the mean price of electricity offered by solar companies is different in the southern states than in the northern states.You select a random sample of 8 solar companies from the southern states and 11 from the northern states.For the southern states,the average price is 12.2 cents per kWh (kilowatt hour)and the standard deviation is 0.8 cents per kWh.For the northern states,the average and standard deviation are 11.7 and 1.0 cents per kWh respectively.If you use a significance level α = 0.10 and assuming the values are normally distributed in both populations,the critical t value is ______.
A) 1.330
B) 1.729
C) 1.734
D) 1.740
E) 1.747

Question

Quizplus · Accepted Answer

The critical t value is determined by the degrees of freedom and the significance level. With 8 and 11 samples, the degrees of freedom can be approximated using the smaller sample size minus one, which is 7. At a significance level of 0.10 for a two-tailed test, the critical t value is approximately 1.740.

You Are Interested in Determining Whether the Mean Price of Electricity