Statistics and Mechanics Flashcards
what do you include when commenting on data?
measure of location and spread
how do you make an estimate within data?
with a regression line
what is H0 and H1?
H0 is the hypothesis that you assume to be true. H1 is the opposite.
what happens to the significance level with a two tailed test?
it is split between the two tails.
how do you find that two events are independent?
P(a and b) = P(a)*P(b)
what is the difference between y on x and x on y regression lines?
y on x reduces vertical deviation from the line (residuals) and x on y reduces horizontal deviation
what is a causal relationship between data?
if one changes, the other changes too
what things have to be true to have a binomial distribution?
fixed number of trials (n)
two possible outcomes
fixed probability of success
independent trials
what is P(A|B)?
P(A∩B) / P(B)
what are the points of inflection on the normal distribution graph?
μ ± σ
what is a census?
every member of a population observed
what is stratified sampling?
population is divided into mutually exclusive groups such as males and females and a random sample is taken from each
what is systematic sampling?
every Nth member is observed
what is opportunity sampling?
measuring members of the population available at the time
what is quota sampling?
population is divided into groups. individuals are chosen from each to represent the entire population.
what is the equation for standard normal distribution?
Z = (X-μ) / σ
how do you convert binomial distribution to normal distribution under the right conditions?
μ = np σ^2 = npq
how is X̄ normally distributed?
X̄ ~ N (μ, σ^2 / n)
what is the explanatory variable?
independent variable
how are outliers defined?
they are 1.5 * IQR outside the IQR
what are the percentages on a bell curve that represent μ + nσ.
68% for one σ
95% for 2σ
99.7% for 3σ
What is the difference and similarity between quota and stratified sampling?
Quota sampling is opportunistic but samples are ignored if the quota they belong to is full.
They both have mutually exclusive groups that are filled based of the proportion of that group in the whole population.