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Flashcards in STATS REVIEW FACTS Deck (55)
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1
Q

Critical Z-score for confidence level of 90%

A

1.65

2
Q

Critical Z-score for confidence level of 95%

A

1.96

3
Q

Critical Z-score for confidence level of 99%

A

2.58

4
Q

How do you determine a confidence interval?

A

Mean +/- z-score(SE)

5
Q

How do you determine standard error?

A

Standard deviation/ square root of the sample size (N)

6
Q

What is special about a z-distribution?

A

It has an idealized mean of 0 and a standard deviation of 1

7
Q

Type 1 Error

A

Null is True, but rejected the null

*Said there was a difference when really there wasn’t one!

8
Q

Type 2 Error

A

Null is false, but fail to reject the null

*Said there was no difference but there actually was!!!

9
Q

What are the 3 main parts of the classical experiment?

A
  1. Independent and dependent variables
  2. Pre-testing & post-testing
  3. Control & Experimental Groups
10
Q

Phase 1 of clinical trial

A

Safety & Side Effects

11
Q

Phase 2 of clinical trial

A

Ideal dosing

12
Q

Phase 3 of clinical trial

A

Experimental vs. Control

13
Q

Phase 4 of clinical trial

A

Continued evaluation of FDA-approved therapy

14
Q

What is the hawthorne effect?

A

Research attention affects behavior

15
Q

What does double blind mean?

A

Both the researcher and respondents don’t know which person in control or experimental

16
Q

External Invalidity

A

Applicability to the real world

17
Q

Internal Invalidity

A

Anything other than the stimulus that influences results

  • history
  • Maturation
  • Testing
  • Instrumentation
18
Q

Simple Random Sample

A

Need a list/Sample frame
Assign number
Select a random number

19
Q

Systematic Random Sample

A
  • Determine number of elements needed
  • Divide population by sample number desired = “k”
  • List and number elements
  • RANDOMLY select start point
  • Select every K-th element within groups
20
Q

Stratified

A

Random sample from sub populations

21
Q

Cluster

A
Cluster = groups of elements
Multistage = listing and sampling

**increases sampling error potential - two samples double the error opportunity!

22
Q

Two ways to reduce sampling error

A
  • Increase sample size

- Increase homogeneity

23
Q

What percent of the population falls with-in 1 standard deviation of the mean?

A

68%

24
Q

What percent of the population falls with-in 2 standard deviations of the mean?

A

95%

25
Q

What percent of the population falls with-in 3 standard deviations of the mean?

A

99.7%

26
Q

Prevalence

A

ppl w disease/ # of ppl at risk

27
Q

Incidence

A

new ppl w disease/ 3 of ppl at risk (make sure to subtract ppl who previously contracted the disease)

28
Q

Attack Rate

A

new cases/ # of ppl exposed

29
Q

Secondary Attack Rate

A

new cases / (# exposed - # of primary cases)

30
Q

Sensitivity

A

TP/ (TP + FN)

31
Q

Specificity

A

TN/ (TN + FP)

32
Q

Positive Predictive Value

A

TP/ (TP + FP)

33
Q

Negative Predictive Value

A

TN/ (TN + FN)

34
Q

CER

A

Control Event Rate = proportion of control with bad outcomes

35
Q

EER

A

Experimental Event Rate = proportion of experimental with bad outcomes

36
Q

Absolute Risk

A

Difference btw CER and EER

37
Q

ARR

A

When CER > EER

Increased rate of adverse outcomes in control group

38
Q

ARI

A

When CER

39
Q

Relative Risk

A

EER/CER

40
Q

Relative Risk Reduction/Increase

A

1 - RR

41
Q

Number Needed to Treat (NNT)

A

NNT = 1/ARR

42
Q

Number Needed to Harm (NNH)

A

NNH = 1/ARI

43
Q

Nominal Measurement

A

Measures a mere difference

your hometowns

44
Q

Ordinal Measurement

A

Measures differences + rank order

(Place finish in race- first, second, third)

Socioeconomic status- low or high

45
Q

Interval Measurement

A

Measures difference + rank order + equal distances between values of variable

(Temp)

Does not have true meaningful zero, even when it is 0 degrees outside, there is still a temperature

46
Q

Ratio Measurement

A

Measures differences + rank order + equal distances between values of the variable + true meaningful zero point

(Height & weight)

47
Q

Categorical measurements

A

Nominal

Ordinal

48
Q

Continuous measurements

A

Interval

Ratio

49
Q

If you have 2 categorical measurements, what statistical test would you use?

A

Chi-squared

50
Q

If you have one nominal and one interval-ratio measurement, what test would you use?

A

T-test

51
Q

What is an odds ratio?

A

The “odds” that some outcome would occur in the presence of a predictor vs. absence of the predictor

52
Q

Odds ratio > 1

A

Exposure associated with higher odds of outcome

53
Q

Odds ratio

A

Exposure associated with lower odds of outcome

54
Q

Odds ratio = 1

A

Exposure does not affect odds of outcome

55
Q

How do you calculate odds ratio?

A

AD/BC