ANSWERS SURE A+
✔✔mean (expected value) - ✔✔integral all x(x*f(x))dx
✔✔Normal PDF - ✔✔normalcdf(-inf,x,mean,stddev)
✔✔Standard Normal PDF - ✔✔normalcdf(-inf,x,0,1)
✔✔probability density function - ✔✔For a continuous random variable X, a probability
density function(pdf) such that
1) f(x)>=0 means the function is always nonnegative
2)integral over all x(f(x))dx = 1
3) P(a<X<b) = integral from a to b(f(x)dx = area under f(x)dx from a to b
4)f(x) = o means there is no area exactly at x.(4 is IMPORTANT)
✔✔standard deviation - ✔✔sqrt of V(X)
sqrt(sigma^2)
✔✔standardization - ✔✔Any normally distrubuted random variable, X, with any
population mean, mu, and any population variance, sigma^2, can be transferred into a
standard normal random variable, Z, as follows:
Z= (X-mu) / sigma
✔✔variance - ✔✔V(X) = E(X^2) - μ^2
✔✔E(X^2) - ✔✔mean
E(X) =Σ(all x) x*p(x)
✔✔Z - ✔✔Normal Random Variable
✔✔phi(z) - ✔✔P(Z<z) using chart or invnorm(z,mu=0, sigma=1)
✔✔Histogram - ✔✔A histogram is a visual display of a frequency distribution
Steps to construct a histogram:
1) Label the bin boundaries on the horizontal scale. Label the axis by the name of the
data collected.
2) Mark and label the vertical scale with the frequencies. Label this axis Frequency
3) Above each bin, draw a rectangle whose height is equal to the frequency
corresponding to that bin
, ✔✔Pareto Chart - ✔✔A Pareto chart, named after Vilfredo Pareto, is a type of chart that
contains both bars and a line graph, where individual values are represented in
descending order by bars, and the cumulative total is represented by the line.
✔✔Population Mean - ✔✔the sum of the values in the population divided by the
population size
✔✔Population Variance - ✔✔σ²
✔✔population standard deviation - ✔✔σ
✔✔sample mean (x-bar) - ✔✔sum of the observations divided by the total number of
observations
✔✔sample variance - ✔✔s²
✔✔sample standard deviation - ✔✔S
✔✔ analytic study - ✔✔Analytic studies are done to test specific hypotheses
✔✔cause and effect - ✔✔Cause and effect refers to a relationship between two
phenomena in which one phenomenon is the reason behind the other
✔✔empirical model - ✔✔Empirical modeling refers to any kind of modeling based on
empirical observations rather than on mathematically describable relationships of the
system modeled.
Empirical: based on, concerned with, or verifiable by observation or experience rather
than theory or pure logic
✔✔hypothesis testing - ✔✔a statement about a process behavior value compared to a
claim about another process value, data is gathered to support or refuse a claim
✔✔mechanistic model - ✔✔built from our underlying knowledge of the basic physical
mechanism that related several variables
ex: ohms law
current = V/R
I = E/R
✔✔observational study - ✔✔a study where data is collected in the present by a passive
observer