(M) Data Analysis Part 2 Flashcards
Existing criterion “truth” based on the gold standard
Validity
- Is the percentage of people with the disease who are detected by the test
- Is the percentage of people with the disease who are not detected by the test
- Is the percentage of people with the disease who are correctly labelled by the test as not disease
A. PREDICTIVE VALUE OF A POSITIVE TEST
B. %FALSE NEGATIVE
C. %SENSITIVITY
D. %SPECIFICITY
CBD
- Is the percentage of people without the disease who are incorrectly labelled by the test as having disease
- Is defined as the likelihood that an individual with a positive test has the disease
- Is defined as the likelihood that a person with a negative test does not have the disease
A. PREDICTIVE VALUE OF A NEGATIVE TEST
B. PREDICTIVE VALUE OF A POSITIVE TEST
C. %FALSE POSITIVE
CBA
pa-study nalang ng formula, thanks
oks
The ratio of the chance of the test being positive if having the condition compared to the chance of testing positive if not having the condition.
Positive Likelihood Ratio +LR
The ratio of the chance of the test being negative if having the condition compared to the chance of testing negative in not having the condition.
Negative Likelihood ratio -LR
● Also termed as “reproducibility” or “repeatability”
● Refers to the stability or consistency of information
● The extent to which similar information is supplied when
measurements are performed more than once
RELIABILITY
A key goal in applied biostatistics is to make inferences about unknown population parameters based on sample statistics
INFERENTIAL STATISTICS
- a range of values, derived from sample statistics, that is likely to contain the value of an unknown population parameter.
- Because of their random nature, it is unlikely that two samples from a particular population will yield identical confidence intervals
- But if you repeated your sample many times, a certain percentage of the resulting confidence intervals would contain the unknown population parameter.
Confidence interval
- ratio or interval form of measurement
- nominal scale of measurement;
categorized - studying one population but comparing it to a gold standard
A. One Sample
B. Dichotomous Variable
C. Continuous Variable
CBA
two types of estimates for each population
parameter:
○ Point estimate
○ Confidence interval (CI) estimate.
a range of likely
values for the population parameter based on:
○ The point estimate, e.g., the sample mean
○ The investigator’s desired level of confidence (most commonly 95%, but any level between 0-100% can be selected)
confidence interval estimate (CI)
With smaller samples (n< 30) the Central Limit Theorem does not apply, and another distribution called the _______________ must be used
t distribution
similar to the standard normal
distribution but takes a slightly different shape depending on
the sample size.
t distribution
t values are listed by
degrees of freedom (df)
a contention or assumption made concerning a population’s characteristics. It is usually concerned with the parameters of the population about which the statement is made
Statistical Hypothesis
- The purpose of the research is to provide evidence to support or refute the null hypothesis
- Comprises a set of procedures.
- either rejected or not based on the probability of occurrence of the sample results if the null
hypothesis were true
Hypothesis in testing
imma skip this part, alam niyo na ‘yan
Include values of statistics leading to rejection of null
hypothesis.
CRITICAL REGION OR REGION OF REJECTION
Include values of statistics leading to rejection of null hypothesis. Usually called
These values are those whose probability of occurrence is less than or equal to the level of significance, α.
alpha or tail of the curve.
Satatistical tests
What statistical test should be used to compare a single population with interval/ratio data?
Z Test or T test
What statistical test should be used to compare a single population with ordinal data?
Kolmogorov
Smirnov one
sample test
What statistical test should be used to compare a single population with nominal data?
Z Test
Chi square Test
