Tefloncoated pots and pans are designed to be nonstick and to make cooking and clean-up easier. A recent study compared the thickness of the Teflon layer in new, factory-coated pans with recoated pans. A random sample of pans was obtained for each group, and the Teflon thickness was carefully measured (in inches).
a. Find a 95% confidence interval for the population mean Teflon thickness in factory-coated pans.
b. Find a 95% confidence interval for the population mean Teflon thickness in recoated pans.
c. Is there any evidence to suggest these two population means are different? Justify your answer.
Most people understand that highly processed, carbohydrate-heavy foods are not very healthy. However, we often justify a carbohydrate-rich meal by vowing to “eat healthy” next time. A new study suggests that those who eat a high-carbohydrate meal start to crave even more of these foods shortly afterwards.51 An experiment was conducted to test this claim. Researchers gave two groups of adults similar test meals, one of which was rich in carbohydrates. After four hours, brain scans were used to determine if there was activity related to reward, craving, and addictive behavior. The following results were obtained.
a. Find a 99% confidence interval for the true proportion of people who exhibit addictive behavior after eating a low-carbohydrate meal.
b. Find a 99% confidence interval for the true proportion of people who exhibit addictive behavior after eating a high-carbohydrate meal.
c. Is there any evidence to suggest that the proportion of people who exhibit addictive behavior is different after eating a high- or low-carbohydrate meal?