Research Concepts Flashcards
Audit vs research?
Research: designed to generate new knowledge
Audit: assess whether a service meets a standard
What is the null hypothesis?
No relationship exists between two sets of data.
What does it mean if null hypothesis is true?
Observed effect is due to chance alone
What are the levels of evidence? 3
Level 1: systematic reviews, high quality RCT
Level 2: cohort, case control, quasi experimental
Level 3: case study, expert opinion, pre test/post test studies
What is a case control study?
Compares 2 groups (cases, controls) in real time. Similar groups, cases have disease and controls do not.
When to use a case control?
1.data on exposure is difficult to obtain
2. Disease is rare or long incubation period
3.population difficult to follow up
Example of case control?
Chemical/pesticide exposure linkage to disease
What is a cohort study?
Follow a group of people over a period. Study how certain factors affect their health over time. Have a common experience eg birth year, geographic area
What is a meta analysis?
A type of analysis/calculation that estimates effect size
What is a mixed methods study?
Uses both qualitative and quantitative data
Eg how does student perceptions of their school influence their test scores?
What is an independent variable?
A variable that the researcher can control or not affected by any other variable in the study
What is a nominal/categorical variable?
Anything that be in a category eg yes/no, hair colour
What is ordinal data?
An ‘ordered’ hierarchical data eg socioeconomic status (low, med, high)
What is an interval ratio?
Anything that has same measurement between levels eg pain 1-10 (has 1 between each level), temp
Has no absolute zero
What is continuous ratio?
Has an absolute zero eg blood pressure readings, distance
What is a type I error and how is it determined?
False positive: rejection of null hypothesis when it’s actually true.
Alpha value
What is a type II error?
False negative: accepting null hypothesis when it is false
Depends on sample size or statistical power
What is validity?
How accurate a test is
What is reliability?
How consistent a test is
What is the formula for sensitivity?
TP/(TP+FN)
What is a frequency distribution?
Graph or table that shows frequency counts
What are the 3 measures of central tendency?
Mean
Median
Mode
Central tendency: What is the mode?
The most frequent appearing value.
Central tendency: What is the mean?
The sum/number of observation ie the average
Central tendency: What is the median?
The middle value across a dataset
What do you do if there are two middle values in a dataset?
Sum them, then divide by two
When to use median as a measure of central tendency?
Asymmetrical data set ie 11 observations
What is a Z-score?
The relationship of a specific value to the mean
Eg Z-score=0 means it is exactly the same number as mean
Z-score=1 means it’s 1 SD away
What is the Z-score formula?
Z=(x-M)/G
X: value of interest
M: mean
G: SD
What is positive predictive value?
The proportion of people who test positive who are true positives
What is sensitivity?
Accuracy
The proportion of people who have a disease, that test positive
