Location

Question 1

mean (x with bar on top)=

Answer 1

sum of X value/n
In grouped data sum of fx/sum of f

Question 2

position of Q1, Q2 and Q3 8 listed data

Answer 2

Q1 = n/4
Q2=n/2
Q3=3n/4
if decimal
Round up and find position of that
If whole number find the mid points with the next number

Question 3

Grouped data postposition of q1 q2 and q3

Answer 3

Q1 n/4
Q2 n/2
Q3 3n/4
Then use linear interpolation

Question 4

Working out percentiles of grouped data

Answer 4

%/100 x n
Then use linear interpolation

Question 5

Define deciles

Answer 5

10% chunks
Eg d3 is 30% percentile

Question 6

IQR =

Answer 6

Formula booklet

Question 7

Advantage of interquartile range

Answer 7

Ignores extremes

Question 8

Variance for listed data

Answer 8

Sum of x^2/n - mean ^2
Mean of squares minuse square of means

Question 9

Variance for grouped data

Answer 9

Sum of f(x^2) / sum of f -mean ^2

Question 10

Is data coded to y=ax +b the mean and standard derivation is

Answer 10

mean of y = a(mean of X) +b
Standard derviation of y = a (standard deviation of x)

Question 11

Median, q2 and q3 and extreme values and minimum on cumatlive frequency and how can be used to draw box plot

Answer 11

Read from the y-axis at certain points and the X-axis value corresponds to value on box plot
Q2 middle
q1 1/4
Q3 3/4
Extreme value very top and very bottom

Question 12

Outlier boundaries

Answer 12

Q1 -1.5 xIQR
Q3 +1.5

Question 13

why should you use a histrogram

Answer 13

continuous data
(no gaps)

Question 14

Histrogram:
Freq density =
Area =

Answer 14

Freq dems= frequency/ classwidth
Area = freq x k

Question 15

when comparing 2 diagrams what should you talk about

Answer 15

location (mean)
and spread (variance, standard derivation and interquatile range)
with context