Flashcards in Equations Deck (22):

1

## Maintenance dose

### =(Cp * CL * time) / F

2

## Loading dose

### =(Cp * Vd ) / F

3

## Volume of distribution

### Vd = (total amount in body) / (Cp)

4

## Half life

### = (0.69 * Vd ) / CL

5

## Clearance

### = (Rate of elimination) / Cp = Vd * Ke

6

## Sensitivity

###
=Proportion with disease test +.

= TP / (TP + FN)

=1 - FN rate

Rule out.

7

## Specificity

###
=Proportion that test neg without disease.

= TN / (TN + FP)

=1 - FP rate

8

## Positive predictive value

###
= TP / (TP + FP)

Varies directly with prevalence.

9

## Negative predictive value

###
= TN / (TN + FN).

Varies inversely with prevalence.

10

## Odds raio (OR)

### = (odds that group with disease was exposed to risk factor) / (odds that the group without disease was exposed)

11

## Relative risk (RR)

###
= (risk of developing dz if exposed) / (risk if not exposed

If low prevalence, OR ~ RR

12

## Attributable risk (AR)

###
= (risk if exposed) - (risk unexposed)

Looks at adverse events.

e.g. risk of lung cancer in smoker = 21%, non-smoker 1%, then 20% attributable to smoking.

=(RR-1)/RR

13

## Absolute risk reduction (ARR)

### = (risk if exposed) - (risk unexposed)

14

## Number needed to treat

### = 1 / ARR

15

## Number needed to harm

### = 1 / AR

16

## Standard error of the mean

### = (standard deviation sigma) / sqr(n)

17

## Normal distribution

###
Mean = median = mode

1 sigma = 68%

2 sigma = 95%

3 sigma = 99.7%

18

## Type I Error (alpha)

###
= False-positive error.

alpha = saw a difference that did not exist.

19

## Type II Error (beta)

###
= False-negative error.

beta = blind to a difference that did exist.

20

## Confidence Interval

### = range from [mean - Z(SEM)] to [mean + Z(SEM)]

21

## Power

### Power = 1 - beta

22