1. The WHO recommend that cholesterol levels should be below 200. Cholesterol levels for a group of individuals were recorded, and are detailed in the following table:
. (a) What is the standard error of the mean cholesterol level?
. (b) Determine (at the 1% level) whether the average cholesterol level for the patients detailed adheres to the WHO recommendation. Clearly state any assumptions on which your conclusion relies. ?
. (c) Construct a 95% confidence interval for the mean cholesterol level and interpret the resulting interval.
2. A researcher wants to investigate whether women are better at multi- tasking than men. She conducts an experiment where each participant is given a newspaper article to read while dialogue is played into the room. The participant is then given a test afterwards on the contents of the article and dialogue. The score on the test determines multi-tasking skills (higher score implies better at multi-tasking). The results of the study for 21 male participants and 16 female participants are as follows
x s n
Males 50.2 9.8 21
Females 60.5 5.2 16
. (a) Is there evidence in the data to suggest that the mean multi- tasking score for females is at least 5 points greater than that for ?males? (Take ? = 0.05)
. (b) Construct a 90% confidence interval for the mean difference in multi-tasking scores and interpret it.