Reference no: EM133920304

Question

Researchers have collected blood samples on 489 adults aged 45 years of age or older, including prolactin levels (ng/mL). They hypothesize that prolactin levels in blood decline with age. The data for this study can be found in the excel data file located in the Data Sets folder in A2L and is called BLOOD.xlsx. In the data set, 'ageblood' represents the age (years) of the participant and 'prolactin' represents their prolactin level (ng/mL). Prolactin in the adult population (18 years of age or older) is known to have a mean of 12 ng/ml. Use the data in the data set BLOOD.xlsx to answer the questions below.

1. Create a plot of the prolactin levels for people in the sample that are over the age of 65 years. Comment on the shape of the distribution.

2. Researchers would like to use the sample data in BLOOD.xlsx to test the hypothesis that people over the age of 65 years have prolactin levels less than the average for the general adult population (12 ng/ml). They are considering using the one-sample z test to test this hypothesis. Would this test be appropriate given your observations from question a?

3. Conduct the appropriate statistical procedure to test the researchers' hypothesis that people over the age of 65 years have prolactin levels less than the mean for the general adult population (12 ng/ml). Assume α=0.05. Show all calculations.