Brainscape's Knowledge GenomeTM

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


See full index

MB > Stats+Research > Flashcards

Stats+Research Flashcards

1
Q

What values can the correlation coefficient range between?

A

Correlation coefficient can range from -1 to +1

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

What value is the correlation coefficient represented by?

A

r

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

What are the values of the categories of degree of correlation?

A

0-0.2 negligible

  1. 2-0.5 weak
  2. 5-0.8 moderate
  3. 8-1 strong
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What does standard deviation measure?

A

Spread of a set of observations - variability of the obseervations

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

What is the formula for standard deviation?

A

square root of variance

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

What does a low standard deviation mean?

A

Data points tend to be very close to the mean

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

What does a high standard deviation mean?

A

Data points tend to be spread out over a large range of values

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

Is variance expressed in the same units as the data?

A

No

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

As the SD increases what happens to the SEM?

A

increases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

As sample size increases what happens to the SEM?

A

Decreases

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

What’s the SEM?

A

A measurement of the precision of the sample mean as an estimate of the population mean

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

What is snowball sampling?

A

identifying participants with certain characteristics and getting them to identify more participants

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is Absolute risk reduction?

A

Absolute risk reduction is the difference in risk of a given event between two groups.
Formula = CER - EER

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

What is the confidence interval?

A

Confidence interval is the range of values within which one can be 95% certain that the true reference population value lies

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

What is the NNT?

A

Number needed to treat is the number needed to treat to get one good outcome or to prevent one additional outcome
Formula = 1/ARR

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

What is the relative risk?

A

Relative risk is the ratio of the risk of a given event in one group of subjects compared with another group
Relative risk = EER/CER
Relative risk reduction = ARR (CER-ERR)/CER

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

What is the relative risk reduction

A

Relative risk reduction is the proportion of the initial or baseline risk that was eliminated by a given treatment or by avoidance of exposure to a risk factor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are case-control studies ideal for?

A

Rare diseases/outcomes

-partcularly useful for situations where there is a long time period between exposure and outcome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What type of bias are case-control studies at risk of?

A

Recall bias

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is face validity?

A

The extent to which a test measures what it’s supposed to measure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is reliability?

A

How consistent a test is on repepeated measurements

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is predictive validity?

A

The extent to which a test is able to predict something it should theoretically be able to predict

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is inter rate reliability?

A

The level of agreement between assessmentsmade by two or more raters at the same time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is contruct validity?

A

The extent to which a test measures a theoretical connstruct by a specific measuring device or procedure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is Cronbach’s alpha?

A

It indicates the internal consistency of a test (the reliability)
-infinity to 1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is criterion validity?

A

predictive and concurrent validity together.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What randomisation technique minimises contamination between intervention and control group?

A

Cluster

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What is an independent t test used for?

A

Used to compare the means of two independent different sample populations - parametric test so assumes samples are normally distributed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What is a paired t test used for?

A

Used for matched studies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What is a crossover study?

A

longitudinal study in which subjects are allocated to sequences of treatment with purpose of studying differences between individual treatments - all subjects eventually receive all the same treatments

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What is continuous scale + an example?

A

Data with no break in values and includes all possible data

e.g weight

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What is an interval scale + an example?

A

Scale without an absolute zero, there are meaningful intervals between measurements
e.g. temp in farenheit

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What is a nominal scale + an example?

A

Classification of observatiosn into unordered qualitative categories
e.g. bood group, ethnicity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What is a ratio scale + an example?

A

Interval scale with a true zero point

  • thye are useful in regression
    e. g. temp in Kelvin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What is an ordinal scale + an example?

A

Classiification of data into ranked categories

  • data have order but the interval is meaningless
    e. g. Hamilton Rating Scale for Depression (HAM-D) score
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What is volunteer bias?

A

Those who agree to participate in the study tend to be healthier and more compliant than those who dont

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

What is selection bias?

A

Presence or absence of exposure influences allows allocation to particular study groups

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

What is ascertainmnent bias?

A

If data is more accurate or complete in one group than the other

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

What method in qualitative research can increases the validity of the study?

A

The use of multiple coders for validating emerging themes provides a mode of triangulation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

How might using a single interviewer in qualitiative research be a weakness?

A

Using a single interviewer can affected the relevant experiences reported by the interviewed subjects

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

What type of sampling is used in most qualitative studies?

A

purposive sampling

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

What is moderator bias?

A

The moderator’s nonverbal and verbal attitude, expressions, body language, approach etc. may introduce bias. Similarly, the moderator’s demographics such as gender, age, social status, race and accent can also affect the interview content.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

Why is purposive sampling used in qualitative studies?

A

maximises the chance of obtaining a range of views relevant for a qualitative study

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

The use of topic guides along with a time-limited interviewing is what type of interview?

A

semi-structured approach.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

What’s the formula for the likelihood ratio of positive test?

A

Sensitivity / (1-Specificity)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

What’s the formula for the likelihood ratio of negative test?

A

1 - sensitivity / specificity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

What’s the formula for the false positivity rate?

A

1-specifity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

What’s the formula for the NNT?

A

1/ARR

ARR = response in control group - response in exposure group

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

What’s a sequenced parallel RCT and what’s the purpose?

A

The sequenced parallel comparison design has been recently proposed by Fava et al. to reduce the impact of placebo response issue in drug trials. It is a design that identifies and removes early placebo responders.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

TWO methods that help address potential bias in a meta-analysis

A
  • considering papers not published in english

- using wider literature search

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

Choose TWO methods that help address heterogeneity in a meta-analysis

A
  • random effect analysis

- Chi-square test

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

Which method is most useful to assess publication bias?

A

funnel plot

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

What is a measure of heterogeneity in meta analysis?

What % should heterogeneity be?

A

The I² statistic describes the percentage of variation across studies that is due to heterogeneity rather than chance. The rule of thumb is that you want the I² to be less than 50%. You will notice there are other statistics there like x² and z. Just focus on the I² as this is the most useful in interpreting a forest plot

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

How to work out 95% CI of NNT from 95% CI of ARR

A

Low limit = 1/higher limit of CI of ARR

Upper limit = 1/lower limit of CI of ARR

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

In a Gaussian distribution what is the expected value of kurtosis ?

A

3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

What can be used to quanitify reliability?

A

Cronbach’s alpha
Cohens statistic
Kappa
Intraclass correlation coefficient

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

Which tests can show normality?

A

Lilliefors corrected test
Anderson Darling test
Kolgomogorov-Smirnov test
Shapiro-Wilk test

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

Efficacy vs effectiveness

A

Efficacy - research trials

Effectiveness - real life

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

Cohen’s effect size values

A

Cohen’s d is an appropriate effect size for the comparison between two means.

  1. 2 = small
  2. 5 = medium
  3. 8 = large
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

Do RCTs have highexternal validity?

A

No

This is about applicability in the real world

61
Q

Perfect cut off point on ROC curve

A

0,1

62
Q

X axis on ROC curve

A

false positive

63
Q

Y axis on ROC curve

A

true positive

64
Q

Purpose of using composite endpoint

A

Power of study is increased

65
Q

What bias does allocation concealment help to reduce?

A

Allocation concealment helps to reduce selection bias

66
Q

What bias does blinding help to reduce?

A

Blinding helps to reduce ascertainment/measurement bias.

67
Q

What will be the percentage of type 1 error if the results of a trial are precisely meeting the conventional level of significance?

A

5%

68
Q

When the same psychiatrist applies screening tool and carries out diagnostic assessment in a research study that evaluates the diagnostic tool, it can lead to what type of bias?

A

Information

69
Q

Which analysis converts outcomes into monetary units?

A

cost benefit

70
Q

Which analysis converts outcomes into Clinical

measurement scales?

A

cost effectiveness

71
Q

What analysis converts outcomes into any natural

units (days saved,number of deaths prevented, or QALYs etc.)?

A

Cost consequences

72
Q

What analysis converts outcomes into life

utility units e.g. DALY, QOL, etc.?

A

Cost utility

73
Q

What analysis is used when both interventions produce same outcome and hence just the costs are compared?

A

Cost Minimisation

74
Q

What is opportunity cost?

A

Opportunity cost is defined as the benefit that a resource would yield in its best alternative use.

The benefits of next best foregone alternatives when the available resources are utilised in one way

75
Q

Which factor is not important in determining the quality of a meta-analysis?

A

Magnitude of outcome reported from individual studies

76
Q

What is the non-parametric alternative to paired t-test?

A

Wilcoxon signed rank test

77
Q

What is the the non-parametric alternative of the unpaired t test?

A

Mann-Whitney U test

78
Q

What is Kruskal-Wallis test ?

A

Kruskal-Wallis test compares between the medians of two or more samples to determine if the samples have come from different populations (non parametric)

79
Q

What is ANOVA?

A

ANOVA test compares between the means of two or more samples to determine if the samples have come from different populations (parametric)

80
Q

What is an agreed method of assessing quality of conducting and reporting systematic reviews and metaanalyses?

A

QUORUM

81
Q

What are measures of internal consistency of a test?

A

Cronbach’s α

Split half reliability

82
Q

The ability of a test to correctly classify subjects as being with or without a disease is called?

A

Likelihood ratio

83
Q

What’s the lifetime prevalence of depression in those with anorexia?

A

75%

84
Q

The pre-test probability is equal to:

A

Prevalence

85
Q

When are confounders important?

A

Confounding factors are only important if they differ between the arms of a study

86
Q

What is an evidence-based, minimum set of recommendations for reporting RCTs

A

CONSORT

87
Q

The guideline most suited to Non-randomised controlled trials

A

TREND

88
Q

The guideline most suited to Meta-analyses

A

QUORUM

89
Q

What is an evidence-based minimum set of items for reporting in systematic reviews and meta-analyses

A

PRISMA

90
Q

What is a proposal for reporting a meta-analysis of observational studies in epidemiology

A

MOOSE

91
Q

The guideline to improve the reporting of observational studies in the field of epidemiology

A

STROBE

an international, collaborative initiative of epidemiologists, methodologists, statisticians, researchers and journal editors involved in the conduct and dissemination of observational studies, with the common aim of STrengthening the Reporting of OBservational studies in Epidemiology

92
Q

The consensus checklist recommended when reporting formal studies of healthcare quality improvemen

A

SQUIRE

93
Q

The guideline most suited to Diagnostic studies

A

STARD

94
Q

The guideline most suited to Microarray studies

A

MIAME

95
Q

The guideline most suited to Qualitative studies

A

COREQ

96
Q

The medical database where you can obtain abstracts published since 1890 is

A

Pychinfo

97
Q

Medline has items from which year?

A

1949

98
Q

Cohort studies are especially prone to this bias

A

Attrition bias

99
Q

A structured approach whereby research ethics committees review proposals for RCTs

A

ASSERT

A Standard for the Scientific and Ethical Review of Trials

100
Q

Number of deaths during a calendar year expressed in terms of midperiod population of the area

A

Crude mortality rate

101
Q

Any study comparing incidence rates must have

A

a specified denominator

102
Q

Exposure data are available for groups but not for their individual members in these studies

A

Ecological

103
Q

What is ecological fallacy?

A

Ascribing the characteristics of a group to all individuals in that group

104
Q

Disadvantages of carrying out a cohort study?

A

Time resources, manpower and monetary costs

105
Q

Which study design is best suited to evaluate properties of a screening tool?

A

Cross sectional design

106
Q

What is work up bias (verification bias)?

A

a systematic error in the assessment of the validity of a diagnostic test

107
Q

What is family aggregation bias?

A

type of information bias
–> presence of a case in the family increases awareness of risk factors and exposure leading to more family members of cases reporting an exposure though controls have family members with less awareness.

108
Q

When is Per-protocol analysis often carried out?

A

in biological explanatory RCTs and as the secondary analysis in effectiveness trials

109
Q

Which trials have high external validity?

A

Pragmatc trials

110
Q

What test can be used for adjusting for confounding factors when analysing the relationship between a dichotomous outcome and a dichotomous risk factor? (odds ratios)

A

The Mantel-Haenszel technique

111
Q

Matching is most suitable for which studies?

A

Smaller studies i.e. small case control

*It is not needed for RCTs and extremely difficult for large cohort studies. It is not possible for ecological studies and cross-sectional surveys.

112
Q

What is pygmalion effect?

A

The Pygmalion effect is also called the experimenter expectancy effect. Pygmalion is Bernard Shaw’s play where a professor bets and succeeds in teaching a poor flower girl to speak and act like a higher-class lady. Mere awareness of the experimenter’s expectations regarding treatment effect may result in a change in subject behavior in the direction of experimenter hypothesis.

113
Q

In grounded theory method of qualitative research, the term theoretical saturation is used to describe?

A

Point at which no new categories can be developed from the available data

114
Q

In which research method might the clear cut demarcation between researcher” and “researched” may not be so apparent?

A

Action research

115
Q

Theoretical sampling is associated with

A

Developing a theory for further research

116
Q

What can be used to demonstrate the validity of a qualitative study?

A

Reflexivity in reporting results
Triangulation
respondent checking
Deviant case analysis

117
Q

What is reflexivity?

A

Recognition of the researcher’s preconceptions and their influence on interpretation and analysis

118
Q

In qualitative studies, semi-structured interviews are often chosen over other forms of interviews. This is because

A

Good balance between resource limitations and amount of data collected

119
Q

What is the most important factor to consider for reliability oof a qualititative study?

A

triangulation

member checking

120
Q

What is a problem inherent in all qualitative studies?

A

Generalisability is a problem inherent in all qualitative studies.

121
Q

One of the advantages of using a constant comparative approach for for data-analysis is?

A

The emerging categories can be refined in a flexible manner

122
Q

Which research technique used during a qualitative study can inform the number of participants necessary for a given sample?

A

Saturation

123
Q

Weighting refers to the level of significance attached to the outcome of individual studies considered in a meta-analysis. Which factors are considered for weighting?

A

Impact factor of the published journal
Sample size of studies
Methodological rigour of studies
Precision of results

124
Q

In which situation is a random effects analysis is indicated in a meta-analysis?

A

Presence of statistical heterogeneity

125
Q

What is the effect size measured in meta-analyses?

A

Difference in outcome between intervention and control groups in terms of standard deviation of the outcome in the population

126
Q

Who coined the term meta-analysis?

A

Glass

127
Q

Incremental cost-effectiveness ratio (ICER) formula

A

ICER = Cost of proposed intervention / effect of proposed intervention.

128
Q

Which two parameters are required for constructing a cost-effectiveness analysis curve?

A

Willingness to pay and probability of cost effectiveness

129
Q

In a cost-effectiveness plane which quadrant indicates best cost effectiveness of an intervention?

A

Southeast

130
Q

In economic analysis what is the cost of pain and suffering from an intervention that cannot be quantified in monetary terms?

A

Intangible costs

131
Q

Which method of quality improvement is based on 80/20 rule of management?

A

Pareto Chart

132
Q

Reducing waste is a critical part of which of models of quality improvement?

A

Lean Thinking

133
Q

What is age specific mortality rate used for?

A

Used to compare mortality between same age groups in different regions

134
Q

Mediation model rules

A
  1. The predictor (i.e. treatment) must be significantly related to the outcome (i.e. response)
  2. The predictor must also be significantly related to the potential mediator
  3. The mediator must be significantly related to the outcome when the effect of the predictor on the outcome is controlled for
  4. The relationship between predictor and outcome must be reduced when controlling for the mediator (i.e. pathway c’ having effect lower than the pathway c).
135
Q

If predictor remains significant when the mediator is controlled for

A

the mediation is considered partial

136
Q

If predictor is non signifcant when the mediator is controlled for

A

mediation is considered complete

137
Q

Most common level of prevention currently employed in psychiatric practice is

A

Tertiary

138
Q

The incidence of schizophrenia is three times higher in migrants, but this drops to 1.8 times higher than natives when point prevalence rates are considered. This can be explained by

A

Shorter duration of illness in migrants

139
Q

The phenomenon of relative deprivation is explained by

A

Jarmen index

140
Q

According to the pathways of care model, illness behaviour is a strong determinant at which of the following filters between disease and secondary psychiatric care?

A

First stage - self recognition

141
Q

What is it when two or more experimental interventions are not only compared separately but also in combination and against a control in an RCT?

A

factorial RCT

142
Q

What is a a Guttmann Scalogram useful in measuring?

A

hierarchical constructs e.g. social attitudes, political views, developmental stages,

143
Q

Which data is better suited for weighted kappa compared to Cohen’s Kappa for measuring agreement?

A

Ordinal

144
Q

Which factors affect the external validity of a study?

A
  • Representativeness of the sample
  • Reactive effects of setting (is the research setting artificial)
  • Effect of testing (if a pre-test was used in the study that will not be used in the real world this may affect outcomes)
  • Multiple treatment inference (this refers to studies in which subject receive more than one treatment, the effects of multiple treatments may interact)
145
Q

What is an example of a filtered resource?

A

The Database of Abstracts of Reviews of Effect (DARE)

146
Q

The Kolmogorov-Smirnov and Jarque-Bera tests are used to test for

A

Normality

147
Q

The chance that the patient does not have the condition if the diagnostic test is negative

A

NPV

148
Q

How much the odds of the disease decrease when a test is negative

A

LR-ve

MB (16 decks)

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