Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Math > statistics > Flashcards

statistics Flashcards

1
Q

population

A

A collection of all items.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

statistic

A

A function of the sample that contains no unknown quantities.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

raw data

A

Information that can be obtained from a population.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

disadvantages of a census

A
  • time consuming and expensive
  • cannot be used when the testing process destroys the item
  • hard to process large quantity of data
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

advantage of a census

A

It should give a completely accurate result.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

census

A

Observes or measures every member of a population.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

sample

A

Observations taken from a subset of the population.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

advantages of a sample

A
  • less time consuming and expensive than a census
  • fewer people have to respond
  • less data to process than in a census
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

disadvantages of a sample

A
  • data may not be as accurate as a census
  • sample may not be large enough to give info about small subgroups of the population
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

sampling units

A

Individual units of a population.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

sampling frame

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

3 sampling techniques when there is access to the whole population

A
  • simple random
  • stratified
  • systematic
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Never Get In Cold Soup

A

Number
Generate
Ignore
Continue
Select

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

random integer generator in calculator

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

stratified sampling

A

Samples taken from each group in proportion to their size.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

systematic sampling

A

Members of the population are chosen at regular intervals.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

advantages of simple random sampling

A
  • free of bias
  • easy and cheap to implement for small samples
  • each sampling unit has a known and equal chance of selection
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

disadvantages of simple random sampling

A
  • not suitable when sample size is large
  • a sampling frame is needed
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

advantages of systematic sampling

A
  • simple and quick to use
  • can introduce bias if sampling frame is not random
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

advantages of stratified sampling

A
  • sample accurately reflects the population structure
  • guarantees proportional representation of groups within a population.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

disadvantages of stratified sampling

A
  • population must be clearly classified into distinct strata
  • selection within each stratum suffers the same disadvantages as simple random sampling
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

3 sampling techniques when there is not access to whole population

A
  • opportunity
  • quota
  • cluster
23
Q

opportunity sampling

A

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

24
Q

quota sampling

A

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

25
Q

cluster sampling

A

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

26
Q

advantages of opportunity sampling

A
  • easy to carry out
  • inexpensive
27
Q

disadvantages of opportunity sampling

A
  • unlikely to provide a representative sample
  • highly dependent on individual researcher
28
Q

advantages of quota sampling

A
  • 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
29
Q

disadvantages of quota sampling

A
  • 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
30
Q

advantages of cluster sampling

A
  • easy to carry out
  • inexpensive (if few clusters)
31
Q

disadvantages of cluster sampling

A
  • bias is more likely (size of cluster changes probability)
  • only useful when population can be naturally divided into easily identifiable clusters
32
Q

variance formula in terms of standard deviation

A

variance = standard deviation²

33
Q

Independent variable on a scatter graph

A

X axis

34
Q

Dependent variable on a scatter graph

A

Y axis

35
Q

causal relationship

A

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

36
Q

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

A

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

37
Q

mutually exclusive

A

When events have no outcome in common.

38
Q

P(A∪B) for mutually exclusive events

A

P(A) + P(B)

39
Q

independent events

A

When one event has no effect on another.

40
Q

discrete data

A

Data that takes values which change in steps.

41
Q

random variable

A

A variable whose value is determined by chance.

42
Q

discrete uniform distribution

A

All probabilities are the same.

43
Q

criteria for binomial distribution

A
  • fixed number of trials
  • 2 possible outcomes
  • fixed probability
  • trials are independent of each other
44
Q

probability that a random continuous variable takes a specific value

A

0

45
Q

features of a normal distribution graph

A
  • bell shaped
  • symmetrical about the mean
46
Q

total area under a normal distribution graph

A

1

47
Q

what is μ and σ in X~N(μ, σ²)

A

μ is the mean and σ is the sd

48
Q

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

A

3 standard deviations from the mean

49
Q

standard normal distribution notation

A

Z~N(0, 1)

50
Q

formula to convert standard normal

A

X = μ + Zσ

51
Q

standard deviation of the probability of the mean of a sample

A

standard deviation / √sample size

52
Q

normal distribution hypothesis if above sig level

A

accept H₀

53
Q

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

A

the sample is not random

Math (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions