A group of researchers is studying the relationship between cortisol (stress hormone) levels and memory, and they want to see if a sample of 100 adults that has been recruited is a good representation of the population it came from, before they conduct additional research. The population has been found to be normally distributed and have a mean cortisol level of 12 mcg/dL, with a standard deviation of 2 mcg/dL. The sample was found to have a mean cortisol level of 15 mcg/DL, with a standard deviation of 3 mcg/dL.

construct a confidence interval to determine if this sample mean is significantly different from the population mean. Explain how you know, based on the confidence interval, and specify the confidence level you used. Be sure to show your work and calculations. This can be tricky with Word, so if necessary you may take a photo of your hand calculations and add it to the Word document.

Be sure to include supporting detail from the readings, as well as other scholarly sources.