Statistics Year 1

Question 1

what is a population

Answer 1

a whole set of items/people that are of interest

Question 2

what is a census

Answer 2

a measure of every member of a population

Question 3

what is a sample

Answer 3

a part of a population which is being used to find out info about an entire population

Question 4

what are sampling units

Answer 4

individual units of a population

Question 5

what is a sampling frame

Answer 5

when sampling units are individually named or numbered

Question 6

simple random sampling

Answer 6

where every sample has an equal chance of being selected

Question 7

systematic sampling

Answer 7

the required elements are chosen at regular intervals from an ordered list

Question 8

stratified sampling

Answer 8

the population is divided into mutually exclusive strata (e.g male and female) and a random sample is taken from each

Question 9

quota sampling

Answer 9

a researcher selects a sample that reflects the characteristics of the whole population

Question 10

opportunity sampling

Answer 10

consists of taking the sample from people who are available at the time the study is carried out and fit the criteria

Question 11

quantitive data

Answer 11

numbers
numerical observations

Question 12

qualitative data

Answer 12

non numerical
doesn’t involve numbers

Question 13

continuous variables

Answer 13

a variable that can take any value in a given range

Question 14

discrete variables

Answer 14

a variable that can only take specific values in a given range

Question 15

what is the mode/modal class

Answer 15

the most common value

Question 16

median

Answer 16

middle value

Question 17

mean

Answer 17

the sum of all/the amount

Question 18

mean in a frequency table

Answer 18

the sum of the products or the data values and their frequencies / the sum of the frequencies

Question 19

interpercentile range

Answer 19

the difference between the values for two given percentiles

Question 20

variance

Answer 20

mean of the squares — the square of the mean

Question 21

standard deviation

Answer 21

the square root of
the mean of the square — the square of the mean

σ

Question 22

common outlier equation

Answer 22

either greater than Q3 + k(Q3-Q1)
or
less than Q1-k(Q3-Q1)

Question 23

on a histogram what is the area of a bar

Answer 23

k x frequency

Question 24

on a histogram, when k = 1,
how do you calculate the frequency density

Answer 24

frequency / class width

Question 25

what comparing data what can you comment on?

Answer 25

a measure of location a measure of spread

Question 26

Bivariate data

Answer 26

data which has pairs of values for two variables

Question 27

what is the variable called that can be controlled

Answer 27

independent / explanatory

Question 28

what is the variable called that is being measured

Answer 28

dependent / response

Question 29

what are the different types of correlation

Answer 29

strong negative correlation weak negative correlation no linear correlation weak positive correlation strong positive correlation

Question 30

what does correlation describe

Answer 30

the nature of the linear relationship between two variables

Question 31

what is a causal relationship

Answer 31

where a change in one variable causes a change in the other a correlation does not mean they have a causal relationship

Question 32

does a correlation always mean a causal relationship

Answer 32

no

Question 33

what is the equation for a regression line of y on x

Answer 33

y = a + bx

Question 34

On a regression line, what does the coefficient b tell you

Answer 34

positive b - positively correlated negative b - negatively correlated

Question 35

What must you not do when making predictions from Bivariate data

Answer 35

you must not make predictions for values of the independent variable only the dependent variable that is within the given data range

Question 36

what is interpolation

Answer 36

when estimating the value of the dependent variable from a regression line within the given data

Question 37

what is extrapolation

Answer 37

when estimating the value of the dependent variable from a regression line outside the given data making it much less reliable

Question 38

what is an experiment

Answer 38

a repeatable process that gives a number of outcomes

Question 39

what is an event

Answer 39

a collection of one or more outcomes

Question 40

what is a sample space

Answer 40

the set of all outcomes

Question 41

what is an intersection on Venn Diagrams

Answer 41

A and B - where they overlap

Question 42

what is a union on a Venn Diagram

Answer 42

A or B or both

Question 43

what is a complement of A on a Venn Diagram

Answer 43

everything but A P (not A) = 1 - P(A)

Question 44

what is it called when events have no outcomes in common

Answer 44

mutually exclusive in a venn diagram the curves will not overlap

Question 45

what is the formula for mutually exclusive events

Answer 45

P (A or B) = P(A) + P(B)

Question 46

what is it called when one event has no effect on the other

Answer 46

independent

Question 47

what is the formula for independent events

Answer 47

P(A and B) = P(A) x P(B)