Please show your work. Thank you.

Question 1:

Study of obesitymales and females between the ages of 20 and 75:

n # overweight

Males 120 18

Females 280 70

What is p-hat (males)?

What is p-hat (females)?

What is p-hat, the weighted average of the two proportions?

Question 2:

If x-bar = 100 and s = 20 (units completely theoretical and unimportant) and n = 25, calculate a 95% confidence interval for the true population mean :

Lower limit (to two decimal places) is:

Upper limit (to two decimal places) is:

Value of t/Z used is:

Question 3:

Skin testing was done with an antigen from the bacterium Mycobacterium ulcerans in a 2000 study by Dobos et al.. The odds ratio for developing a skin reaction for subjects receiving burulin vs. subjects receiving controls is (to one decimal place):

Agent

Induration > 10 mm (positive skin reaction) Burulin Control

Yes 17 3

No 12 18

Question 4:

A hypothetical regression equation may be:

headcirc (cm) = 8.31 + 0.45 (gestational age - weeks) + 4.71 (birthweight - kg)

Predict the average head circumference a 30-week old birth weighing 1.1 kg (round to nearest whole number):

Predict the average head circumference a 27-week old birth weighing 0.8 kg (round to nearest whole number):

If the birthweight of two babies is identical, predict the difference in head circumference if the gestational age differs by two weeks (to one decimal place)?