Equations

Question 1

Maintenance dose

Answer 1

=(Cp * CL * time) / F

Question 2

Loading dose

Answer 2

=(Cp * Vd ) / F

Question 3

Volume of distribution

Answer 3

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

Question 4

Half life

Answer 4

= (0.69 * Vd ) / CL

Question 5

Clearance

Answer 5

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

Question 6

Sensitivity

Answer 6

=Proportion with disease test +.
= TP / (TP + FN)
=1 - FN rate
Rule out.

Question 7

Specificity

Answer 7

=Proportion that test neg without disease.
= TN / (TN + FP)
=1 - FP rate

Question 8

Positive predictive value

Answer 8

= TP / (TP + FP)

Varies directly with prevalence.

Question 9

Negative predictive value

Answer 9

= TN / (TN + FN).

Varies inversely with prevalence.

Question 10

Odds raio (OR)

Answer 10

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

Question 11

Relative risk (RR)

Answer 11

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

If low prevalence, OR ~ RR

Question 12

Attributable risk (AR)

Answer 12

= (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

Question 13

Absolute risk reduction (ARR)

Answer 13

= (risk if exposed) - (risk unexposed)

Question 14

Number needed to treat

Answer 14

= 1 / ARR

Question 15

Number needed to harm

Answer 15

= 1 / AR

Question 16

Standard error of the mean

Answer 16

= (standard deviation sigma) / sqr(n)

Question 17

Normal distribution

Answer 17

Mean = median = mode
1 sigma = 68%
2 sigma = 95%
3 sigma = 99.7%

Question 18

Type I Error (alpha)

Answer 18

= False-positive error.

alpha = saw a difference that did not exist.

Question 19

Type II Error (beta)

Answer 19

= False-negative error.

beta = blind to a difference that did exist.

Question 20

Confidence Interval

Answer 20

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

Question 21

Power

Answer 21

Power = 1 - beta

Question 22

Relative risk reduction (RRR)

Answer 22

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

=1-RR