Inferential Stat Flashcards
Find the Value of K
Must add up to 1
Add all and set equal to 1
find E(x) with a table
Rewrite the table with k
Multiply the top and bottom
Add all up
When finding P(X=x) you must…
Include ALL possibilities
How to solve binomial dist. problems with an exact number + at most
use binomial pdf
find
number of trials
p=probability
x= amount trying to find
solve
Find the expected number of something
Multiply probability by the total amount
How to solve binomial dist. problems with at least a number + less than
Use binomial CDF
number of trials ( the same for any question)
probability (the same)
x= 1 fewer than the given number
calculate and subtract from 1
Binomial dist. more than
Use Binom CDF
Subtract 1 - normal calculations
Binomial dist. less than
Binom cdf
Normal calc just x-1
how do you find the variance of a binomial dist. ?
total * prob. * (1-prob)
When given Z ~ N(0,1) what do you plug in
Plug into NormCDF
Use upper/lower limit
doesn’t matter if its less than or equal to
When given Z ~ N(#, #) not (0, 1)
Plug into NormCDF
Square root the second number
Plug 1st into mean
Plug 2nd into SD
Find P given mean and area
Graph problem
Find probability of mean (.50)
Subtract .5- entire thing ,
Variance
standard deviation squared
how to find the value of a variable with standard deviation and mean
Use invNorm
plug in equal
plug in mean + SD
z score
Z= X(raw data)-mean/standard deviation
When do you use a z-score
Normal distribution
Standard deviation
Finding probability with a Z~ N(#,#)
Given Z ~ N(0,1), use graphing calc
P(#<Z<a) =#
Draw on paper g
Plug into NormCDF to find Z<1
Find P(Z<a)-P(Z<1) = #
Add P(Z<1) to number to find a
Plug A into InvNorm
Null hypothesis (H0)
The hypothesis did not work
Alternative hypothesis (H1)
the hypothesis did work
If the probability is less than or equal to the predicted amount…
Reject the H0
If the probability is greater than the predicted amount…
Fail to reject the H0
Z test
Exact amount of numbers for something
2 samp z test
quantifiable amount of numbers for something
ex. hours
1-prop z test
qualitative comparison
2- prop z test
percentages
How do you find p?
plug known numbers into what test it is
what do you write after you either reject or FTR the hypothesis
either restate the claim if its Reject or debate the claim if its FTR
