Statistics Y10 Summarising Data, Scatter Graphs and Correlation EoT test

Question 1

what are avergaes

Answer 1

measures of central tendency or location

Question 2

what is the mode for discrete data

Answer 2

the value that occurs most often

Question 3

what is bimodal data

Answer 3

data with two modes

Question 4

what is the median for discrete data

Answer 4

the middle value in an ordered list

Question 5

calculate the median value for discrete data

Answer 5

1/2(number of values+1)

Question 6

what is the mean for discrete data

Answer 6

the sum of all the values divided by the number of values

Question 7

calculate mean for discrete data

Answer 7

Σ values / number of values

Question 8

what is the mode for grouped data

Answer 8

the group with the highest frequency

Question 9

calculate mean for grouped discrete data

Answer 9

Σ frequency*value / Σ frequency

Question 10

calculate the median value for continuous data

Answer 10

1/2(number of values)

Question 11

estimate median using linear interpolation

Answer 11

L + ((n/2 - F) / f) * w
L = lower boundary or median class
n = number of values
F = cumulative frequency up to median class
f = frequency of median class
w = width of median class

Question 12

estimate mean for continuous data

Answer 12

Σ frequency*midpoint / Σ frequency

Question 13

calculate geometric mean

Answer 13

nth root (value1 * value2 … * value n)

Question 14

what happens to the averages when all the data values are increased by the same amount/percentage

Answer 14

the averages are increased by the same amount/percentage

Question 15

calculate weighted mean

Answer 15

Σ value*weight / Σ weight

Question 16

calculate range

Answer 16

largest - smallest value

Question 17

calculate upper and lower quartiles for discrete data

Answer 17

Q1 = 1/4 (number of values + 1)th value
Q3 = 3/4 (number of values + 1)th value

Question 18

calculate upper and lower quartiles for continuous data

Answer 18

Q1 = 1/4 (number of values)th value
Q3 = 3/4 (number of values)th value

Question 19

calculate interquartile range

Answer 19

upper quartile - lower quartile

Question 20

calculate standard deviation for discrete data

Answer 20

square root( (Σx² / n) - (Σx / n)² )

Question 21

calculate standard deviation for continuous data

Answer 21

square root( (Σfx² / Σf) - (Σfx / Σf)² )

Question 22

calculate boundaries for outliers

Answer 22

lowest < (Q1 - 1.5 * IQR)
highest > (Q3 + 1.5 * IQR)

Question 23

calculate skew

Answer 23

3(mean - median) / standard deviation

Question 24

what variable is on the x-axis

Answer 24

independent/explanatory

Question 25

what variable is on the y-axis

Answer 25

dependent/response

Question 26

what is a correlation

Answer 26

an association between variables

Question 27

what is interpolation

Answer 27

estimating the value of a variable within the range of the data set

Question 28

what is exterpolation

Answer 28

estimating the value of a variable outside the range of the data set

Question 29

calculate gradient

Answer 29

change in y / change in x

Question 30

calculate y-intercept

Answer 30

meanY - gradient * meanX

Question 31

calculate spearman’s rank correlation coefficient

Answer 31

1 - (6 * Σd²) / (n * (n² - 1) )
d = difference between ranks (lowest > highest) of each variable
n = number of data values

Question 32

what is perason’s product moment correlation coefficient suitable for

Answer 32

random samples from normal distribution