Biostatistics and Calculations

Question 1

Data Types (ratio, interval, nominal, ordinal)

Answer 1

Ratio - continuous, meaningful 0
Interval - continuous, no meaningful 0
Nominal - discrete, name
Ordinal - discrete, order

Question 2

Type I vs Type II Error

Answer 2

Type I: false positive (reject the null hypothesis when it shoul have been accepted)
Type II: false negative (accept the null hypothesis when it should have been rejected)

Question 3

Risk calculation

Answer 3

number of subjects in a group with unfavorable event / total number of subjects in that group

Question 4

Relative risk calculation

Answer 4

risk in treatment group / risk in control group
(x% AS likely)

Question 5

Relative risk reduction calculation

Answer 5

1 - RR
(x% LESS likely)

Question 6

Absolute risk reduction calculation

Answer 6

% risk of control group - % risk of the treatment group

Question 7

Number needed to treat calculation

Answer 7

1 / ARR (round UP with NNT, DOWN with NNH)

Question 8

How many mL in an ounce?

Answer 8

30 mL in 1 ounce

Question 9

What is equivalent to 5 mL?

Answer 9

Teaspoon

Question 10

How many ounces in a cup? cups in a pint? pints in a quart? quarts in a gallon?

Answer 10

8 ounces in a cup, 2 cups in a pint, 2 pints in a quart, 4 quarts in a gallon

Question 11

How many centimeters in 1 inch?

Answer 11

2.54 centimeters in 1 inch

Question 12

How many mg in 1 grain?

Answer 12

65 mg in 1 grain

Question 13

Metric ordering

Answer 13

Kilo –>–> deca –base –> deci –> centi –> milli –>–>–> micro –>–>–> nano

Question 14

BMI calculation

Answer 14

weight (kg) / height (meters^2)

Question 15

IBW calculation

Answer 15

50 OR 45.5 + (2.3 x inches over 5 ft)

Question 16

ABW calculation

Answer 16

IBW + 0.4(TBW-IBW)

Question 17

CrCl calculation

Answer 17

[(140-age) / (72 x Scr)] x weight (0.85)
TIA dosing

Question 18

Specific gravity

Answer 18

g/mL

Question 19

BUN:Scr ratio

Answer 19

> 20:1 = dehydration

Question 20

Anion gap calculation

Answer 20

AG = Na - Cl - HCO3 (high = > 12)

Question 21

kcal from protein

Answer 21

4 kcal/gram

Question 22

kcal from dextrose

Answer 22

3.4 kcal/gram

Question 23

kcal from fat

Answer 23

10%: 1.1 kcal/mL
20%: 2 kcal/mL
30%: 3 kcal/mL

Question 24

Maximum calcium + phosphate

Answer 24

45 mEq/L

Question 25

BSA calculation

Answer 25

square root of (height (cm) x weight (kg)/3,600)

Question 26

For an acid, % ionized when pH is above pKa vs when pH is below pKa

Answer 26

pH < pKa –> unionized
pH > pKa –> ionized

Question 27

pH calculation

Answer 27

Acid: pH = pKa + log(salt/acid)
Base: pH = pKa + log(base/salt)

Question 28

ANC calculation

Answer 28

WBC x (seg x band)

Question 29

% ionizatoin calculation

Answer 29

Acid: 100 / 1+ 10^(pKa- pH)
Base: 100 / 1+ 10^(pH - pKa)

Question 30

Aminophylline to theophylline calculation

Answer 30

ATM (a –> t) multiply by 0.8