formulas Flashcards
Petersen Capture - Recapture Formula
M/N=m/n
M=total tagged at start
N=population (unknown)
m=number tagged in sample
n=sample size
Stratified sampling calculation
(Total in stratum / Total population) × sample size
Angles in pie chart
(Frequency / Total) × 360
Comparative Pie Chart
√(F1) /√(F2)= r1/r2
Interquartile Range (IQR)
Q3−Q1
Frequency density
Frequency / class width
Geometric Mean
n^√value 1 * value 2 * … * value n
Weighted Mean
∑(weight × value) / ∑weight
Index number
(price / base year price) × 100
Weighted index number
(weighted mean / base year weighted mean) × 100
Chain base index numbers formula
(Price / last year’s price) × 100
Standard Population
(number in age group / total population) ×1000
Standardised
rate
(crude rate / 1000) × standard population
Absolute Risk
Number of trials in which event happens / Total number of trials
Relative Risk
Risk for those in group / Risk for those not in group
General Addition Formula for probability
P(A∪B) = P(A) + P(B) − P(A∩B)
Multiplication Formula for independent events
P(A∩B) = P(A) × P(B)
Conditional Probability Formula
P(A│B) = P(A∩B) / (P(B)
A and B are independent if
P(A∩B) = P(A)P(B)
Mean for binomial distribution
number of trials * probability of success
Formula for binomial
n^Cr p^(n-r) q^r
n^Cr p^r q^(n-r)
Standardised Score
(score − mean) / standard deviation
Warning limits
Warning limits = 𝜇 ± 2σ
Action limits
Action limits = 𝜇 ± 3σ
