Prevalence
HOW MUCH of a disease exists at a specific point in time
Measures the number of ALL cases (new and pre-existing) of disease/injury in a population at a specific time
Incidence
HOW FAST a disease is occurring in a population
Measures the number of NEW cases of disease/injury in a population during a specific period of time
6 main types of studies in order from least to most valid
- Case Studies
- Cross-Sectional Studies
- Case-Control Studies
- Cohort Studies
- Randomized Control Trial (RCT)
- Systematic Reviews & Meta Analysis
Sometimes Expert Opinions is listed. It is lower than case studies in validity
Observational study type characterized by very small sample size and no control group
Case Studies
Observational study type characterized as a “snapshot” of exposure and outcome at a point in time and measures prevalence
Cross-Sectional Study
Which study type measures prevalence?
Cross-Sectional Study
Which observational study type begins with first identifying individuals with an outcome, then identifies a group of similar individuals without the outcome (the control group) and is examined retrospectively to determine exposure status?
Case-Control Study
Which observational study type begins with first identifying individuals without an outcome and observed over a period of time (prospectively or retrospectively) to observe how a disease or treatment occurs or progresses?
Cohort Study
Which study type is the gold standard of research for therapeutic and preventive interventions?
Randomized Control Trial
Sample population is not a fair representation of the target population is an example of which type of bias?
Selection/Sample Bias
Participants in a study systematically provide inaccurate or biased responses or behavior is which type of bias?
Subject Bias
When a study participant intentionally states a different response when they know they’re being watched
Hawthorne Effect
Null Hypothesis
Predicts no statistical significance between the variables being studied.
Example…If studying the effects of vaping and caries…the null hypothesis would state that there is no correlation between vaping and caries. The Alternative Hypothesis would be that there IS a correlation between vaping and caries
Alternative Hypothesis
Predicts statistical significance between the variables being studied
Example…If studying the effects of vaping and caries…the null hypothesis would state that there is no correlation between vaping and caries. The Alternative Hypothesis would be that there IS a correlation between vaping and caries
3 measures of Central Tendency
Mean, Median, and Mode
3 measures of variability
variance, standard deviation, and percentiles/quartiles
3 measures of distribution
symmetrical, positive skewed, and negative skewed
How do you measure standard deviation
square root of the variance
variance is the measurement of the spread of data from the mean in a data set
what are the percentages associated with 1, 2, and 3 standard deviations of the mean
1 standard deviation: 68%
2 standard deviations: 95%
3 standard deviations: 99.7%
What type of distribution?
Positive skewed
What type of distribution?
Negative skewed
What type of distribution?
Symmetrical
Typical p-value
0.05
If p < 0.05, what does this mean?
It indicates statistical significance and we reject the null hypothesis.
It’s like saying there’s less than a 5% chance that the evidence we’ve obtained from a study happened due to random chance and that there must be (for example) a correlation between vaping and caries, so we would reject the null hypothesis that states there is no correlation between vaping and caries.
