Question 1

What is probability?[3]

Why is it important to know about probability functions? [3]

When do we apply probability functions?[2]

2.1Use the table below to answer the questions.

Blood Pressure Category

optimal Normal Pre-Htn Htn Total

Male 20 15 15 30 80

Female 2 15 25 25 70

Total 25 30 40 55 150

a)What is the probability of selecting a male with optimal blood pressure?

b) What is the probability of selecting a patient with Pre-Htn or Htn blood pressure?

2.2Consider the following table which cross classifies subjects by CVD and gender.

2.2 Consider the following table which cross classifies subjects by CVD and gender.

CVD Free of CVD Total

Men 35 265 300

Women 45 355 400

Total 80 620 700

a)What proportion of men has prevalent CVD?[2]

b)What proportion of patients with CVD are men?[2]

2.3Consider the following table which cross classifies subjects by their family history of CVD and current (prevalent) CVD status

Family History Current CVD

No Yes Total

No 215 25 240

Yes 90 15 105

Total 305 40 345

Calculate the following probabilities.

c) The probability of Current CVD given that the subject has Family History? [2]

d) The probability of Current CVD given that the subject does not have Family History? [2]