extra

Question 1

Write 4.54066E‒06 in standard mathematical notation.

Answer 1

10^-6

Question 2

if you have to extrapolate the data….

Answer 2

not reliable

Question 3

Describe the effect of removing the outliers on

• the product moment correlation coefficient
• the p-value associated with this correlation coefficient, in each case explaining your answer.

Answer 3

look at if the outliers are going to make the line more linear or not

if removing outliers makes the line less linear….

the pmcc would (probably) be closer to 0 because the scatter is less well modelled by a straight line

p-value would increase because a value which is closer to 0 is more likely assuming there is no correlation

Question 4

when would a p value increase

Answer 4

when the PMCC value is closer to zero

ASSUMING THERE IS NO CORRELATION

Question 5

STRENGTHS + WEAKNESSES for sample collecting method

Answer 5

Strength –

large sample size

Weakness –

• sample is not random
  – removal of outliers may not be justifiable

Question 6

When might PMCC not be conclusive

Answer 6

pmcc may not be appropriate as scatter does not appear to be linear

sample not random so calculating a correlation coefficient may not be valid

correlation and causation are not the same thing

the results of a hypothesis test are only suggestive, not conclusive (although highly suggestive in this case)

Question 7

How can the data be cleaned

Answer 7

data missing


removal of outlier data items

Question 8

how to find sigma x

Answer 8

mean multipled by n

Question 9

how to find sigma x squared

Answer 9

have to rearrange standard deviation formula

Question 10

Explain why procedure A will generate a simple random sample.

Answer 10

Question 11

interpolation vs extapolation

Question 12

excel formula

Answer 12

must have = before anything