A Consumer Group Was Interested in Comparing the Operating Time

Multiple Choice

A consumer group was interested in comparing the operating time of cordless toothbrushes manufactured by two different companies. Group members took a random
Sample of 18 toothbrushes from Company A and 15 from Company B. Each was charged
Overnight and the number of hours of use before needing to be recharged was recorded.
Company A toothbrushes operated for an average of 119.7 hours with a standard deviation of 1.74 hours; Company B toothbrushes operated for an average of 120.6 hours with a standard deviation of 1.72 hours. Do these samples indicate that Company B toothbrushes operate more hours on average than Company A toothbrushes? The correct hypotheses to address this question are

A) H0: µA - µB = 0 and HA: µA - µB < 0
B) H0: µA - µB = 0 and HA: µA - µB ≠ 0.
C) H0: µA - µB = 0 and HA: µA - µB > 0.
D) H0: µA - µB > 0 and HA: µA - µB < 0.
E) None of the above.