Week 3

Question 1

What is ratio

Answer 1

Releationship between 2 numbers,, numerator not necessarily included in the deminontator 5:2= 2.5 sex ratio

Question 2

What is proportion

Answer 2

Numererator necessarily included in the denominator ranges between 0 and 1 how many women in the population 2/4 50%

Question 3

What is Odd

Answer 3

The probability of an event occuring relative to it not occurring different than proprtion its how many are divided by how many are not. If 25 people in 100 people are diabetic odd is 25/75=0.33.

Question 4

What happens when a disease is rare?

Answer 4

Odd esitmates porpotion

Question 5

What is rate

Answer 5

Speed of occurrence of an event over time it is porportion but need a time factor

Question 6

What is prevalence rate

Answer 6

The proprtion of the population that has a given disease at a specified time

Question 7

What is point prevalence rate

Answer 7

with disease at specific time divided by population at same time can times by 1000 to get per 1000 people

Question 8

What is measures of incidence

Answer 8

The proportion of the population at risk that develops a given disease or other attribute during a specified time period

Question 9

How do you measure incidence

Answer 9

Remove people who are not at risk you remove them from the population you can’t get cancer if you already had it

Question 10

What is the formula for incidence rate

Answer 10

new events during specified time period divded by population at risk if 9000 residents were studied and 245 of them already had cancer and a total of 179 new cases has been digonsed what is the ir rate of cancer per 10 000 people 179 divided by 9000-245 times 10,000

Question 11

What is relative risk

Answer 11

How many times as likely it is that someone who is exposed to something will experince a particular health outcome compares to someone who is not exposed

Question 12

What is the formula for relative risk

Answer 12

the top is incidence in exposed a/ a+b divided by incidence in unexposed c divided by c+d

Question 13

What dose it mean if for relative risk you got the number 1.76

Answer 13

If you smoke the chance of you getting the disease is 76%

Question 14

What if you wanted to caculate odds ratio in a table

Answer 14

odds of disease in exposed (a/b) divided by odds of disease in unexposed c/d not a percentage

Question 15

What is random error

Answer 15

Error due to chance

Question 16

What is systematic error

Answer 16

Error due to recognizable source

Question 17

Can you have both random and systematic error

Answer 17

Yes

Question 18

What is precision vs accuracy is measurment

Answer 18

If you have high precision it is reliable with high accuracy is valid

Question 19

Why can insufficient precision happen

Answer 19

The measurment tool is not precise enough
Two indpendent interviewers rate the same differtly using the same scale
The same in

Question 20

What makes a valid measure

Answer 20

It measures what it is suppose to measure
Does not include unnecessary questions
Is able to do what it is designed to do predict discriminate etc

Question 21

What is Misclassification

Answer 21

Putting people into the wrong categories

Question 22

What is non-differential

Answer 22

Usually weakens associations brings estimants closer to the null valuse dilutes the estimate, data collected from one group is inacuarate while the other group is accurate

Question 23

What is differential

Answer 23

Different in different study group effect estimates may change in any direction depending on the particular error both groups are inaccurate

Question 24

What can you do to fix information bias once it occured

Answer 24

Nothing needs to be reduced during study design