Experimental Design and Biostatistics

Module 10 Homework

1)The data below is for a hypothetical study investigating the Systolic Blood Pressure (SBP) of construction workers. The table shows respective measurements of 20 workers along with hours of work per day and the area of the city the work took place.

[You can use Excel-Data Analysis - Regression or

http://vassarstats.net/multU.html]

SBP	Hrs/day	Area
109.6	7	east
107.4	8	east
140.3	9	east
146.5	12	east
98.2	6	east
137.8	9	east
124.1	10	east
113.2	8	east
127.8	9	east
125.3	8	east
108.5	6	west
181.3	13	west
137.4	10	west
146.2	10	west
142.4	9	west
123.7	8	west
129.6	8	west
143.6	9	west
160.7	11	west
148.3	9	west

a) What is the regression equation?

b) Interpret the meaning of the slopes in this problem.

d)At the 0.05 level of significance, determine whether each independent variable makes a contribution to the regression model. Indicate the most appropriate regression model for this set of data.

e) Interpret the meaning of the coefficient of determination.

2) The following table includes the number of mg of a particular drug administered in a treatment, along with the survival outcome of the patient.

	No Death	Death	Total	Probability	Odds
Drug Dose	0	1
3	8	2	10
4	6	4	10
5	5	5	10
6	4	6	10
7	2	8	10

a) Complete the columns with the relevant odds and probabilities for the outcome Y=1, ie death.

b) What is the logistic regression equation?

Use http://vassarstats.net/ - Correlation and Regression - Simple Logistic Regression

c) What is the interpretation of the slope?

d) What is the estimated probability of death for a dose level of 6?