Unit Test — Unit test Answers

A researcher is 95% confident that the interval from 2.9 minutes to 6.83 minutes captures the true mean amount of time mice take to complete a maze for a piece of cheese.Is it plausible that the true mean number of times for all mice to complete this maze may be less than 7 minutes?

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. The conditions for inference have been met. What is the correct 95% confidence interval for the difference in the population means?Find the t-table here.

The owner of a smart watch would like to estimate the mean number of steps they take per day. To do so, they select a random sample of 30 days from the previous year’s data and record the number of steps they took on each of those days. Are the conditions for constructing a t confidence interval met?

Two students want to determine whose paper airplane model can fly the farthest. To put their models to the test, they recruit five friends to participate in a study. Because the friends have varying throwing abilities, the students decide to have each friend throw each model of airplane. To determine which paper airplane each friend throws first, a coin is tossed. The data are displayed in the table, which shows how far each airplane flies to the nearest inch.

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. Are the conditions for inference met?