Exam Technique EXACT WORDING

Question 1

Why ti say cant use values beyond trend to predict?

Answer 1

Because you are extrapolating, and this is unreliable as its not guaranteed trend will continue (1)

Also looks like the trend will BREAK DOWN (1)

Question 2

Why is a vsirbale indepenent

Answer 2

Because it’s not subject to RANDOM VARIATION

Question 3

Remember when a binomial situation is given and they say why can it be modelled as binomial AND poisson what to say

Extra thing to make it specific to question?
n

Answer 3

Independent, number of successes from n trials , CONSTSNT probability succes failure = binomial

But also poission because N IS LARGE AND P IS SMALL

Must also give the numbers ! This is a mark!
- binomial number of successes from n trials so a binomial fits

Question 4

When stating a regression line, what to MAKE SURE TO DI ABOUT THE VARIABLES FOR SECOND MARK

Answer 4

Must name them!, x = , y =

Question 5

When they say PMCC test is not valid what’s the only reason you should quote

Answer 5

Not eliptical shape = not bivariate normal

And say why : because if outlier

Ignore poijts not looking straight, that’s for REGRESSION LINES NOT PMCC, whole point of test is to determine if it is correlated , not to predetermine before😭

Question 6

How to say why a binomial is suitable, exact words for the number of trials?

Answer 6

As it’s counting the number of successes in n trials , binomial is suitbsle

(Indecent , fixed etc etc)

Question 7

What are 2 reasons PMCC TEST could be invalid (distribution is not given)

2 reasons don’t lack

Answer 7

1) that it isn’t RANDOM
2) fact we don’t know distribution means it’s probably not appropriate to do PMCC test in case it ISNT NORMAL

Question 8

What’s 1 reason a thing that requires small effect size chart is accurate

Answer 8

If requires chart means LARGE SAMPLE SIZE, so good