Lab Formulas

Question 1

Varience

Answer 1

((Measurement - x̄)^2 + (measurement - x̄)^2 + …) / (sample size – 1)
or “…” / population size

Where x̄ is the mean

Question 2

Standard Deviation

Answer 2

S.D. = sqrt(variance)

Question 3

Standard Error

Answer 3

S.E. = S.D. / sqrt(n), where n is the sample size; primarily used to find 95% Confidence

Question 4

95% Confidence

Answer 4

95% Confidence = mean ± 1.96(S.E.)

Question 5

Birth, Death, Growth rate

Answer 5

Birth rate = newborns this year/ population
Death rate = deaths this year/ population
Growth rate = Birth rate – Death rate

Question 6

Exponential Growth Equation (Discrete)

Answer 6

N[t+1] = N[t]+ N(r)
where:
N[t+1]: population size at next time interval
N[t]: population size at current time
r: intrinsic rate of population increase

Question 7

Exponential Growth Equation (Continuous)

Answer 7

N[t]= N[0] (e^(rt))
or
ln (N) = ln (N) + rt

Where:
N[t]: population size at time t
N[0]: population size at the beginning
e: base of natural log (~2.718) 
r: intrinsic rate of population increase
ln: natural log
(Honestly, I hate him a lot...)

Question 8

Bailey Correction for Lincoln-Peterson Index

Answer 8

N = M(S + 1) / (R + 1)
where:
N = population size
M = marked animals
S = sample size
R = recaptured marked animals

Question 9

Portion of habitat space available

Answer 9

(Carrying Capacity - Pop Size) / Carrying Capacity

Question 10

Logistic Growth Equation

Answer 10

N = N + N • r • ((K - N) / K)
N[t+1]: population size at next time interval
N[t]: population size at current time
r: intrinsic rate of population increase
K: Carrying Capacity