Lecture 23 - Chance 1

Question 1

What is internal validity

Answer 1

The extent to which the study findings are free from alternative explanations (bias, confounding)

Question 2

What is external validity

Answer 2

The extent to which study findings can be applied to broader populations

Question 3

What is sampling error

Answer 3

The error that occurs just by chance when a sample isn’t perfect representation of population. Commonly just called chance

Question 4

What can be done about the sample error

Answer 4

Increasing the size of the study sample when randomly sampling

Question 5

What does increasing the sample size do

Answer 5

• Reduces sample variability
• Increase likelihood of getting a representative sample
• Increases precision of parameters estimate

Question 6

How to measure influences of sampling error

Answer 6

Using confidence intervals

Question 7

What does a 95% C.I represent

Answer 7

It represents the range within which the true population parameter lies 95% of the time if repeated sampling occurs

Question 8

what are C.I

Answer 8

A more common and intuitive, less-precise, interpretation.
- We are 95% confident that the true population value lies between the limits of the confidence interval.

Question 9

Interpretation of C.I

Answer 9

We are 95% confident that the true value of parameter (OR) lies between the upper and Lower limit.

Question 10

Clinical importance of C.I

Answer 10

C.I can help us decide whether the study findings are clinically important

Question 11

Parameter

Answer 11

The true value of the measure in the population that the study is trying to discover

Question 12

Estimate

Answer 12

The measure found in the study sample, sometimes referred to as the point estimate