Biostatistics

Question 1

Sample

Answer 1

A small part of the population to show what it is like

Question 2

Population

Answer 2

What we are investigating

Question 3

Why don’t we test the population?

Answer 3

Costly and difficult

Question 4

Percent equation

Answer 4

100 x number with characteristic / total number

Question 5

Continuous variables

Answer 5

Can take on any value

Mean, standard deviation

Question 6

Standard deviation

Answer 6

Tells us how far away each observation is from the mean on average

Question 7

Two types of errors

Answer 7

1. Sampling variability

2. Bias

Question 8

Population mean symbol

Answer 8

μ

Question 9

Population standard deviation symbol

Answer 9

σ

Question 10

Sample mean symbol

Answer 10

x̄

Question 11

Sample size symbol

Answer 11

n

Question 12

Sample standard deviation symbol

Answer 12

s

Question 13

Sampling distribution

Answer 13

Variability of sampling distribution is called standard error (SE)

Question 14

Standard error

Answer 14

Standard deviation of the sampling distribution

SE = s/√n

Question 15

Binary variables

Answer 15

Proportion

Question 16

Normal distribution

Answer 16

Symmetrical bell curve

Question 17

95% confidence interval equation for samples

Answer 17

± 1.96 x SE

Question 18

95% confidence interval equation for means

Answer 18

x̄ ± 1.96 x s√n

Question 19

Box plots

Answer 19

The median 50% of the sample is above this point and 50% is below this point
‘25th percentile’ - 25% of sample is below this point and 75% is above
‘75th percentile’ - 75% of sample is below this point and 25% is below

Question 20

What do we need to consider?

Answer 20

• The wording of the question
• Assume there is no difference because we are looking for evidence against
• What results do we expect
• Bias and sampling errors