formulas

Question 1

Petersen Capture - Recapture Formula

Answer 1

M/N=m/n

M=total tagged at start
N=population (unknown)
m=number tagged in sample
n=sample size

Question 2

Stratified sampling calculation

Answer 2

(Total in stratum / Total population) × sample size

Question 3

Angles in pie chart

Answer 3

(Frequency / Total) × 360

Question 4

Comparative Pie Chart

Answer 4

√(F1) /√(F2)= r1/r2

Question 5

Interquartile Range (IQR)

Answer 5

Q3−Q1

Question 6

Frequency density

Answer 6

Frequency / class width

Question 7

Geometric Mean

Answer 7

n^√value 1 * value 2 * … * value n

Question 8

Weighted Mean

Answer 8

∑(weight × value) / ∑weight

Question 9

Index number

Answer 9

(price / base year price) × 100

Question 10

Weighted index number

Answer 10

(weighted mean / base year weighted mean) × 100

Question 11

Chain base index numbers formula

Answer 11

(Price / last year’s price) × 100

Question 12

Standard Population

Answer 12

(number in age group / total population) ×1000

Question 13

Standardised

rate

Answer 13

(crude rate / 1000) × standard population

Question 14

Absolute Risk

Answer 14

Number of trials in which event happens / Total number of trials

Question 15

Relative Risk

Answer 15

Risk for those in group / Risk for those not in group

Question 16

General Addition Formula for probability

Answer 16

P(A∪B) = P(A) + P(B) − P(A∩B)

Question 17

Multiplication Formula for independent events

Answer 17

P(A∩B) = P(A) × P(B)

Question 18

Conditional Probability Formula

Answer 18

P(A│B) = P(A∩B) / (P(B)

A and B are independent if
P(A∩B) = P(A)P(B)

Question 19

Mean for binomial distribution

Answer 19

number of trials * probability of success

Question 20

Formula for binomial

Answer 20

n^Cr p^(n-r) q^r

n^Cr p^r q^(n-r)

Question 21

Standardised Score

Answer 21

(score − mean) / standard deviation

Question 22

Warning limits

Answer 22

Warning limits = 𝜇 ± 2σ

Question 23

Action limits

Answer 23

Action limits = 𝜇 ± 3σ