3 + 4

Question 1

how to find lower quartile (Q1)

Answer 1

n/4

Question 2

how to find upper quartile (Q3)

Answer 2

3n/4

Question 3

with quartiles, if discrete

Answer 3

if not whole no., round up

Question 4

what kind of data is grouped data

Answer 4

continuous data (b/c with interpolation you get more accurate)

Question 5

when finding where the quartile term is in a grouped table, where do you look at

Answer 5

in the cumulative frequency column

Question 6

how to find the range

Answer 6

highest value - lowest value

Question 7

how to find the IQR

Answer 7

Q3 -Q1

Question 8

how to find the xth percentile

Answer 8

xn / 100

Question 9

how to find n% to m% inter percentile range

Answer 9

(like IQR) Pm - Pn

Question 10

how to find variance (o2)

Answer 10

(sum of x)2 / n - (sum of x / n)2

Question 11

how to find standard deviation (o)

Answer 11

o = square root of variance (o2)

Question 12

what does a frequency table look like when finding variance and standard deviation

Answer 12

x / f / fx / fx2

use totals to figure out

Question 13

what does a grouped table look like when finding variance and standard deviation

Answer 13

class / f / x (mid point) / fx / fx2

use totals to figure out

Question 14

what does standard deviation (o) measure

Answer 14

how far away terms are from the mean value (spread)

Question 15

if you use coding, what happens to the standard deviation (o) if you add or subtract a constant

Answer 15

NOTHING

Question 16

if you use coding, what does affect the standard deviation?

Answer 16

multiplying or diving so will have to be reversed

Question 17

what do you draw when drawing a stem and leaf diagram

Answer 17

A KEY

Question 18

what is an outlier

Answer 18

an extreme value in a set of data

Question 19

what is an outlier associated with

Answer 19

box and whisker diagrams / box plot

Question 20

in a box plot, what represents an outlier

Answer 20

an ‘x’

Question 21

how do you calculate the lower outlier

Answer 21

Q1 - (IQR x 1.5)

Question 22

how do you calculate the upper outlier

Answer 22

Q3 + (IQR x 1.5)

Question 23

so what do you actually plot on the box plot as an outlier

Answer 23

any data which is beyond the upper or lower outlier NOT the upper or lower outlier

Question 24

what do you say when comparing 2 sets of data (2)

Answer 24

1. 1 measure of location (medium / Q1 / Q3 is higher or lower)
2. 1 measure of spread (range or IQR)
   USE EXAMPLES

Question 25

what is the relationship between the area and frequency in a histogram

Answer 25

area = kf

area is proportional to frequency

Question 26

what is the triangle used in calculating histograms if k=1

Answer 26

height of block / frequency density = frequency / class width

fd = f / cw so f is at the top

Question 27

when drawing the horizontal line in your histogram, what should you remember

Answer 27

draw in constants (1s, 2s, 5s,) NOT your class boundaries

Question 28

in histograms what should you not forget concerning class boundaries

Answer 28

LOWER AND UPPER BOUNDARIES but there are none if no gaps remember

Question 29

how to know if the question wants you to figure out area = kf

Answer 29

when it says bla bla was REPRESENTED BY A BAR OF WIDTH X AND LENGTH Y

Question 30

how to figure out the skew with quartiles

Answer 30

symmetrical: Q2-Q1 = Q3-Q2
positive: Q2-Q1 < Q3-Q2
negative: Q2-Q1 > Q3-Q2

Question 31

how to figure out skew with ‘measures of location’

Answer 31

symmetrical: mode = medium = mean
positive: mode < medium < mean
negative: mode > medium > mean

Question 32

what are measures of location

Answer 32

mode, medium, mean

Question 33

what are measures of spread

Answer 33

IQR and range

Question 34

how to figure out skew with shape from box blots

Answer 34

symmetrical: medium is in the middle
positive: medium is near the left
negative: medium is near the right

Question 35

what is the formula to figure out skew

Answer 35

3(mean-medium) / standard deviation

Question 36

how to figure out skew using the formula

Answer 36

symmetrical: formula = 0
positive: formula > 0 (aka positive)
negative: formula < 0 (aka negative)