Brainscape's Knowledge GenomeTM

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


See full index

Foundations 1 > Stats > Flashcards

Stats Flashcards

1
Q

Count

A

Cannot be compared b/c they arise from populations of different sizes
Use when important to public health or to allocate resources

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

Ratio

A

Shows relative size of 2 values

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

Proportion

A

Numerator is subset of denominator
Dimensionless
Between 0 and 1

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

Rate

A

a/a+b (can be proportion, always a ratio) over an amount of time

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

Incidence

A

Frequency of the occurrence of new cases over a specified period of time
Measures appearance of disease

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

Cumulative incidence

A

Risk of probability of an individual getting a disease
Proportion: # of new cases of disease/# at risk at beginning of follow up or over a specified time period
Fixed populations

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

Incidence rate

A 
# of new cases/sum of disease-free person-time over specified time period
Takes into account population differences in periods of follow up
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Person-time at risk

A

Sum of disease-free time in population

  1. Add individual risk periods (exact)
  2. Use average number of people multiplied by study duration
  3. Use average duration per person
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Prevalence

A

Proportion of people in a population w/ the disease at a specified point in time
Measures existing disease
Describes health burden

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

Point prevalence

A

Proportion: # of existing cases/total population at a specified point in time

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

Period prevalence

A

Proportion: (# of existing cases + # of cases that occur during the interval)/population at midpoint of interval or avg population size

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

Prevalence-Incidence relationship

A

Prevalence depends on incidence and disease duration
P = ID
If a disease is of short duration, I ~ P
If a disease is chronic, P > I
Prefer incidence b/c interested in etiology and you don’t want to vary too many factors at the same time (birth defect problem)

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

Binary data

A

One of two answers

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

Nominal data

A

Categorical data w/ no order

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

Ordinal data

A

Categorical data w/ order

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

Continuous data

A

Data measured continuously or on integer scale

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

Frequency distribution

A

Means of describing categorical data

Must add up to 100%

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

Mean

A

Average

Limitations: sensitive to extreme values, not ideal for skewed data

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

Median

A

Middle value

20
Q

Mode

A

Most often

21
Q

Variance

A

Average of square of deviations about the sample mean

S^2 = (sum(xk -xbar)^2)/(n-1)

22
Q

Negative skew

A

Number of outlying values on low end (hump is on right)

23
Q

Positive skew

A

Number of outlying values on high end (hump is on left)

24
Q

Standard deviation

A

Square root of variance

Std = sqrt((sum(xk -xbar)^2)/(n-1))

25
Q

Normal distribution

A

Theoretical probability distribution that is symmetric about its mean and is “bell” shaped
Mean = Median = Mode

26
Q

Standard normal distribution

A

Specific distribution with mean of 1 and Std of 1
68% of data w/in 1 std
95% of data w/in 2 std
99.7% of data w/in 3 std

27
Q

Shapiro-Welk test

A

Null hypothesis = data are normally distributed

p < 0.05 means data are NOT normally distributed, reject null hypothesis

28
Q

Screening

A

Presumptive identification of unrecognized disease or condition by application of tests, examination, or other procedures
Attempts to classify asymptompatic people as likely or unlikely to have disease
Goal is to delay onset of symptoms and prolong survival
Only done for healthy people

29
Q

Primary Prevention

A

prevent disease before it starts

30
Q

Secondary Prevention

A

delay symptoms

31
Q

Tertiary Prevention

A

slow disease progression

32
Q

Lead Time

A

duration of time by which diagnosis is advanced as a result of screening

33
Q

Validity

A

Does the test measure what it’s supposed to measure?

Bullseye

34
Q

Internal validity

A

Does the test measure what it’s supposed to measure?

35
Q

External validity

A

Generalizability, how well does the result generalize to the population?

36
Q

Reliability

A

Does the test give the same result over and over?

37
Q

Sensitivity

A

Sensitivity = a / a + c
Number of people who screen positive over number of people who actually have the disease
Increase to prevent disease transmission
Sensitivity + FN = 1

38
Q

Specificity

A

Specificity = d / b + d
Number of people who screen negative amongst those who don’t have disease
Increase for fatal disease w/ no treatment
Specificity + FP = 1

39
Q

True positive

A

Individuals who test positive and have disease

40
Q

True negative

A

Individuals who test negative and don’t have disease

41
Q

False positive

A

Individuals who test positive and don’t have disease
Increased w/ increasing sensitivity
FP = b / b + d
Specificity + FP = 1

42
Q

False negative

A

Individuals who test negative and half disease
Increased w/ increasing specificity
FN = c / a + c
Sensitivity + FN = 1

43
Q

Overall Accuracy

A

Assesses proportion of true test results among all test results
Overall accuracy = A + D / A + B + C + D = TP + TN / TP + FP + TN + FN

44
Q

Positive predictive value

A

Number of people w/ true disease who tested positive divided by number of people who tested positive
Likelihood of having true disease if you test positive
PPV = a / a + b

45
Q

Negative predictive value

A

Number of truly non-diseased people who tested negative divided by number of people who tested negative
Likelihood of not having disease if you test negative
NPV = d / c + d

Foundations 1 (8 decks)

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