Stats Mistakes And Laoarf 2 Flashcards
Remember if choosing two methods
Probability way and how many ways can yiu choose
Or just total combinations for given boundary
And then for two things, can multiply the fhooses
Remember look for number form what’s left, and then choose how many you need , lose the identity
How ti find total different number of combinations
LOOK AT THE DIFFERNT THINGS THERE ARE
So if 3 different
NOW IN FIRST POSTION , DO TOTAL CHOOSE how many of that there are
Now next postion, subtract how many there are, keep repeating
Should get it
If not draw them out
So for example 4 things, 3 same one differnet?
2 same 1 diff 1 diff?
4c3 x 1c1
4c2 x 2c1 x 1c1
Why don’t use mode
If it’s in lower quartile
% much lower than median
- data not repeated so median better
- distribution skewed so median better
% mode not significantly higher like only by 1
More varied data means you have more stuff or less?
Less, talk for both
Don’t lack, remember n in binomial is
How to find p
What’s the same in each box, same 10 per box so n is 10, 100 boxes n isn’t 100
Here mean = np
So if have mean, and n , can roughly say p
Remember ti what these fraud sitirbtuins, first 6 means
Test all numbers and add them up, this will confirm
So less than equal o 6
How to systematic sampling
How many numbers, divide total by thst, now pick a random number and cycle every thatch number until you get 200
If go above numbers, cycle again
Remember if dine twice independently
To multiply
How ti differentiate inverse
Diffenrtiwte normal,
The gradient at y = 3 on inverse is same as 1/ gradient at x =3
Shape of distribution ?
= post I’ve / negative skew
Always factories first
Before going ahead with anything
Remember base log of the big remove sit
LOWER QUARTILE UPPER ORUTLEIR
IS FROM LOWER AUARTIKE AND UPPER,
STANDARD IS FRIM THE MEANNNN
Remmeber ti use formulas rather than tables, and if it’s a sticky condition
Use a table?
