statistics

Question 1

population

Answer 1

A collection of all items.

Question 2

statistic

Answer 2

A function of the sample that contains no unknown quantities.

Question 3

raw data

Answer 3

Information that can be obtained from a population.

Question 4

disadvantages of a census

Answer 4

• time consuming and expensive
• cannot be used when the testing process destroys the item
• hard to process large quantity of data

Question 5

advantage of a census

Answer 5

It should give a completely accurate result.

Question 6

census

Answer 6

Observes or measures every member of a population.

Question 7

sample

Answer 7

Observations taken from a subset of the population.

Question 8

advantages of a sample

Answer 8

• less time consuming and expensive than a census
• fewer people have to respond
• less data to process than in a census

Question 9

disadvantages of a sample

Answer 9

• data may not be as accurate as a census
• sample may not be large enough to give info about small subgroups of the population

Question 10

sampling units

Answer 10

Individual units of a population.

Question 11

sampling frame

Answer 11

A list formed from individually named/numbered sampling units of a population.

Question 12

3 sampling techniques when there is access to the whole population

Answer 12

• simple random
• stratified
• systematic

Question 13

Never Get In Cold Soup

Answer 13

Number
Generate
Ignore
Continue
Select

Question 14

random integer generator in calculator

Answer 14

1 –> PROB –> RAND –> RanInt#(lower, upper, total)

Question 15

stratified sampling

Answer 15

Samples taken from each group in proportion to their size.

Question 16

systematic sampling

Answer 16

Members of the population are chosen at regular intervals.

Question 17

advantages of simple random sampling

Answer 17

• free of bias
• easy and cheap to implement for small samples
• each sampling unit has a known and equal chance of selection

Question 18

disadvantages of simple random sampling

Answer 18

• not suitable when sample size is large
• a sampling frame is needed

Question 19

advantages of systematic sampling

Answer 19

• simple and quick to use
• can introduce bias if sampling frame is not random

Question 20

advantages of stratified sampling

Answer 20

• sample accurately reflects the population structure
• guarantees proportional representation of groups within a population.

Question 21

disadvantages of stratified sampling

Answer 21

• population must be clearly classified into distinct strata
• selection within each stratum suffers the same disadvantages as simple random sampling

Question 22

3 sampling techniques when there is not access to whole population

Answer 22

• opportunity
• quota
• cluster

Question 23

opportunity sampling

Answer 23

Takes samples from members of the population you have access to until you have a sample of the desired size.

Question 24

quota sampling

Answer 24

When you decide how many members of each group you wish to sample in advance then use random sampling.

Question 25

cluster sampling

Answer 25

Population is split into clusters which are randomly selected and then taken a random sample of.

Question 26

advantages of opportunity sampling

Answer 26

- easy to carry out - inexpensive

Question 27

disadvantages of opportunity sampling

Answer 27

- unlikely to provide a representative sample - highly dependent on individual researcher

Question 28

advantages of quota sampling

Answer 28

- allows a small sample to still be representative of the population - no sampling frame required - quicky, easy and inexpensive - allows for easy comparison between different groups within a population

Question 29

disadvantages of quota sampling

Answer 29

- non-random sampling can introduce bias - population must be divided into groups, which can be costly or inaccurate - non-responses are not recorded as such

Question 30

advantages of cluster sampling

Answer 30

- easy to carry out - inexpensive (if few clusters)

Question 31

disadvantages of cluster sampling

Answer 31

- bias is more likely (size of cluster changes probability) - only useful when population can be naturally divided into easily identifiable clusters

Question 32

variance formula in terms of standard deviation

Answer 32

variance = standard deviation²

Question 33

Independent variable on a scatter graph

Answer 33

X axis

Question 34

Dependent variable on a scatter graph

Answer 34

Y axis

Question 35

causal relationship

Answer 35

If a change in one variable causes a change in the other.

Question 36

one reason why a conclusion drawn from a scatter graph may not be valid

Answer 36

There may be a 3rd variable that affects the data.

Question 37

mutually exclusive

Answer 37

When events have no outcome in common.

Question 38

P(A∪B) for mutually exclusive events

Answer 38

P(A) + P(B)

Question 39

independent events

Answer 39

When one event has no effect on another.

Question 40

discrete data

Answer 40

Data that takes values which change in steps.

Question 41

random variable

Answer 41

A variable whose value is determined by chance.

Question 42

discrete uniform distribution

Answer 42

All probabilities are the same.

Question 43

criteria for binomial distribution

Answer 43

- fixed number of trials - 2 possible outcomes - fixed probability - trials are independent of each other

Question 44

probability that a random continuous variable takes a specific value

Answer 44

0

Question 45

features of a normal distribution graph

Answer 45

- bell shaped - symmetrical about the mean

Question 46

total area under a normal distribution graph

Answer 46

1

Question 47

what is μ and σ in X~N(μ, σ²)

Answer 47

μ is the mean and σ is the sd

Question 48

most of the distribution in a normal distribution should be within...

Answer 48

3 standard deviations from the mean

Question 49

standard normal distribution notation

Answer 49

Z~N(0, 1)

Question 50

formula to convert standard normal

Answer 50

X = μ + Zσ

Question 51

standard deviation of the probability of the mean of a sample

Answer 51

standard deviation / √sample size

Question 52

normal distribution hypothesis if above sig level

Answer 52

accept H₀

Question 53

Give one reason why a certain sample should not be used to conduct a hypothesis test.

Answer 53

the sample is not random