STATS AND MECHANICS Flashcards
if y=a x^n , what is log y
log y= log a + n log x
if y= k b^x, what is log y
log y= log k + x log b
what does the product moment correlation coefficient describe
the linear correlation between 2 variables
values for PMCC
between -1 and 1
for a one tailed test of PMCC, what are the hypotheses
H0: ρ=0 H1: ρ<0
OR
H0: ρ=0 H1: ρ<0
for a two tailed test of PMCC, what are the hypotheses
H0: ρ=0
H1: ρ≠0
how can the event A and B be written
A∩B (intersection)
how can the event A or B be written
A∪B (union)
how can the event not A be written
A’ (complement of A)
how is the probability that B occurs given A occurs written
P(B|A)
for independent events what are P(A|B) and P(B|A)
P(A|B)= P(A|B’)=P(A)
P(B|A)=P(B|A’)=P(B)
equation for P(A∪B)
P(A∪B)=P(A)+P(B)-P(A∩B)
equation for P(B|A)
P(B∩A)/P(A)
so P(B∩A)= P(B|A) x P(A)
what is the area under a continuous probability distribution equal to
1
given the normal distribution is symmetrical, what is equal
the mean, median and mode
where are points of infection on normal distribution
μ+σ
μ-σ
standard normal distribution mean
0
standard normal distribution standard deviation
1
conditions required for binomial distribution to be approximated by the normal distribution
n is large (>50)
p is close to 0.5
equations to approximate the binomial distribution by the normal distribution
σ= sqrt (np(1-p))
μ= np
if you are using a normal approximation to a binomial distribution what do you need to apply when calculating probabilities
continuity correction
for a random sample size n taken from a random variable X-N(μ, σ^2), how is the sample mean distributed
X bar -N(μ,σ^2/n)
when using standard normal distribution, P(X<x)=p, what is equation with μ and σ
use P(X<x)=p and inverse normal using standard normal distribution to find A
x-Aσ=μ
equation for moment of F about P
|F| x perpendicular distance
what is the sum of moments acting on a body called
the resultant moment
when a rigid body is in equilibrium what is the resultant force and moment
resultant force in any direction in 0N
resultant moment in any direction is 0Nm
when a rigid body is on the point of tilting about a pivot, the reaction at any other support (or tension in any other wire or string) is what
0
where does mass act on a uniform rod
at midpoint
equation for maximum/limiting value of friction between 2 surfaces
Fmax=μR
μ= coefficient of friction
R= normal reaction between the 2 surfaces
what does the limiting value of friction depend on
the normal reaction R between the 2 surfaces in contact
the roughness of the 2 surfaces in contact
the rougher 2 surfaces in contact are, does μ become smaller or larger
larger
for smooth surfaces what is μ
no friction
μ=0
velocity of horizontal component of a projectile
therefore what equation can be made
constant velocity
a=0
s=vt
acceleration of vertical component of a projectile
constant acceleration due to gravoty
a=g