Consider the following to answer the question(s) below:
A consumer group was interested in comparing the operating time of cordless toothbrushes manufactured by two different companies. They 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?
-Which of the following statements is true?
A) This is a one-tailed test of two dependent means.
B) This is a two-tailed test of two independent means.
C) This is a one-tailed test of two independent means.
D) These samples are matched.
E) This is a two-tailed test of two dependent means.

Question

Consider the following to answer the question(s) below:
A consumer group was interested in comparing the operating time of cordless toothbrushes manufactured by two different companies. They 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? 
-Which of the following statements is true?
A) This is a one-tailed test of two dependent means. 
B) This is a two-tailed test of two independent means. 
C) This is a one-tailed test of two independent means. 
D) These samples are matched. 
E) This is a two-tailed test of two dependent means.

Quizplus · Accepted Answer

This is a comparison of two independent means because the samples are from two different companies. It is a one-tailed test because the question asks if Company B toothbrushes operate more hours on average than Company A toothbrushes.

Consider the Following to Answer the Question(s) Below