Data presentation

Question 1

box plots

Answer 1

DOES NOT SHOW OUTLIERS

Question 2

how to plot a cumulative frequency graph

Answer 2

Plot upper bound of range

Question 3

median / quartiles from cumulative frequency graphs

Answer 3

Median – n+1/2

Quartile – n+1/4 or 3(n+1)/4

(grouped data– don’t add 1 just do n/2)

READ OFF GRAPH

Question 4

histograms - what is area under the graph

Answer 4

Question 5

median from histogram

Answer 5

grouped data - so divide frequency by 2

find the group in this value lies

then linear interpolation it

Question 6

lower quartile from histogram

Answer 6

divide n by 4

find the group in this value lies

then linear interpolation it

Question 7

bivariate data

Answer 7

two variables

Question 8

which variable on x and which on y axis

Answer 8

 Independent variable – x axis
 Dependant variable – y axis

Question 9

better correlation…

Answer 9

closer to a straight line

Question 10

association vs correlation

Answer 10

association refers to any relationship between two variables

correlation is often used to refer only to a linear relationship between two variables

Question 11

what is product moment correlation coefficient

Answer 11

 Between -1 and 1
 -1 – perfect negative
 1 – perfect positive
 0 – no correlation

Question 12

regression line

Answer 12

 Must go through MEAN of x’s and MEAN of y’s
 Go to menu 6 then 2 in the linear format
 Type in values
 And then option – get a b r values