Binomial Distribution Flashcards
How to do hypothesis test 1 tail
Let p be lrobablity
Let x be the nunber of people
H0 =
H1=
Significance level set at 5% or whatever
If H0 is true, x follows BD between (N,p)
P (X<…) =
TEST FOR EXTREME
Now say o value is less or higher
If higher don’t reject if less then it’s too low to happen by chance , so reject
THERE IS INSUFFIEMCT EVIDECNCE AT THE 5% LEVEL
Remember for null hypothesis snd alternstive
DONT PUT DOWN PERCENTAGES
How to find out if H1nhas increased or gone less
Multiply probability with value to find expected. If now values Is lower or higher you know
What errors can iccure with significance levels?
2 ERRORS TAKE HEED
There could be an error where H0 is correct, but because significance level too high, you reject it anyways
The probability if making this error is EQUAL TO SIGNIFICANCE, t
Thus the lower the significance level the better
2) another error is where you reject H0 when yiu should not, again the higher the significance level you increase this
Don’t say certain always say
Insufficent
What happens if you take a larger data set for same success
It is likely that outcome changes, normally if it is not rejected then it might be rejected, a larger dats set Leeds to better results (more conclusive
Okay how to do critical region tests
Basically same as before
Let p be
Let x Be
H0 is
H1 is
Now if Yiu are testing for a higher extreme then finding P (x>=a) <0.05 the lowest value for a
Which is 1 - p (x<=a-1) <0.05
0.95< p
So find highest value that still satisfies this situation
A-1 = that
And so 1 = that +1
So now yiu have a critical region
And if observed value falls in it then reject
If not do not reject
When can a critical region NOT BE ESTABLISHED
If yiu are testing for x < 0 then Yh it can’t be because if x=0 is already likely then there is no critical region as everything passed
With critical region what are you doing
Essentially finding out the values thst if fall in will automatically lead to a rejectionl
Why use?
Because if yiu wwnt to test fir number if samples it becomes easy
How to do TWO TAIL TEST Z
FIRST WHAT IS THE DIFFERENCE
A two tail test is testing for any sort of CHANGE WHATSOVER , good or bad
Thus the H1 is now that the probabiltiy is NO LONGER EQUAL TO WHAT EXPECTED
Here yiu have to test in bith tails , might not be enough evidence ti suggest they went up but enough ti suggest they went down etc
How do you do critical region
Your significance value is in bith tails, so DIVIDE SIGNIFICANCE VALUE BY 2
Then find bith crtical regions that follow this
And then see if kbserved fall
How to to do 2 tail for PORBAILOTY
here you still test in one tail, but assume that this is the same p value in the other tail
Thus at the end MULTIPLY P VALUE BY 2
then test and see
And reject accept
And remember for critical region two tail and orobsbiltuhat you need to do to bith W
Alte erst IV enhootheidd different
Probability x 2 the p value
Critical divide significance by 2
WHAT DOES A NON EMPTY TAIL FOR CRITICAL VALUE Mean
Essentially if 0 satisfies everything its empty
So for it to be non empty atleast 0 gotta not satisfy
And this makes easy too by doing ncr method just simple log
Remember tho log decimal = -, thus switch insauakity