A manufacturer of cell phones would like to estimate how much longer the battery lasts in their model 10 phone than in their model 9 phone. To estimate this difference, they randomly select 40 cell phones of each model from the production line. They subject each phone to a standard battery life test. The 40 model 10 phones have a mean battery life of 14.4 hours with a standard deviation of 2.1 hours. The 40 model 9 phones have a mean battery life of 12.8 hours with a standard deviation of 2.3 hours. A 95% confidence interval for the difference in the population means is (0.594, 2.606). What is the interpretation of this interval?
We can be 95% confident that the interval from 0.594 to 2.606 captures μ1 − μ2 = the true difference in the mean battery life for all model 9 and model 10 cell phones.
We can be 95% confident that the interval from 0.594 to 2.606 captures p1 − p2 = the true difference in the proportion of battery life for all model 9 and model 10 cell phones.
We can be 95% confident that the interval from 0.594 to 2.606 captures the difference in the mean battery life for the two samples of model 9 and model 10 cell phones.
We can be 95% confident that the interval from 0.594 to 2.606 captures the difference in the proportion of battery life for the two samples of model 9 and model 10 cell phones.
