A recent survey was conducted to compare the cost of solar energy to the cost of gas or electric energy. Results of the survey revealed that the distribution of the amount of the monthly utility bill of a 3-bedroom house using gas or electric energy had a mean of 118 and a standard deviation of 8. Three solar homes reported monthly utility bills of 84, 85, and 90. Which of the following statements is true?
A) The utility bills for homes using solar power are about the same as those for homes using only gas and electricity.
B) Homes using solar power may actually have higher utility bills than homes using only gas and electricity.
C) Homes using solar power always have lower utility bills than homes using only gas and electricity.
D) Homes using solar power may have lower utility bills than homes using only gas and electricity.
Question 2
A literature professor decides to give a 15-question true-false quiz. She wants to choose the passing grade such that the probability of passing a student who guesses on every question is less than .10. What score should be set as the lowest passing grade?
A) 11 B) 10 C) 9 D) 12
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