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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

Relative risk reduction (RRR)

= (risk of control - risk of treatment) / risk of control
=1-RR