Math  /  Data & Statistics

QuestionSteve believes that his wife's cell phone battery does not last as long as his cell phone battery. On twelve different occasions, he measured the length of time his cell phone battery lasted and calculated that the mean was 22.3 hours with a standard deviation of 3.2 hours. He measured the length of time his wife's cell phone battery lasted on eight different occasions and calculated a mean of 15.9 hours with a standard deviation of 7.2 hours. Assume that the population variances are the same. Let Population 1 be the battery life of Steve's cell phone and Population 2 be the battery life of his wife's cell phone. Step 2 of 2: Interpret the confidence interval obtained in Step 1.
Answer Tables Keypad Keyboard Shortcuts Since the confidence interval does not contain zero, the data do not provide evidence that the population means are unequal at a 90%90 \% confidence level. We are 90%90 \% confident that the mean battery life of Steve's cell phone is between 2.3 hours and 10.5 hours shorter than the mean battery life of his wife's cell phone. We are 90%90 \% confident that the mean battery life of Steve's cell phone is between 2.3 hours and 10.5 hours longer than the mean battery life of his wife's cell phone. Since the confidence interval contains zero, the data do not provide evidence that the population means are unequal at a 90%90 \% confidence level.

Studdy Solution
We are 90% confident that the mean battery life of Steve's cell phone is between 2.3 hours and 10.5 hours longer than the mean battery life of his wife's cell phone.

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