Week 11 - Treatment Ethics Flashcards
(16 cards)
What is a point estimate
A point estimate is a single value from a sample that estimates the true effect in the entire population.
It helps us infer what might be observed beyond just the sample studied.
What is the mean difference
The mean difference is the absolute difference between the average outcomes of two groups (e.g., treatment vs. control).
What is standardised mean difference
The SMD expresses the size of the treatment effect relative to the variability (standard deviation) in the data.
It is calculated by dividing the mean difference by the standard deviation (usually pooled or baseline SD):
Why use SMD
It standardizes the effect size, allowing comparisons across studies even when different scales or outcome measures are used.
Helpful when replicating experiments or conducting meta-analyses.
SMD may not be appropriate if:
- Data are skewed (not normally distributed).
- The standard deviations of groups differ a lot
What are odds ration and relative risk
Both OR and RR are risk ratios used to compare the risk of an event occurring between two groups.
Commonly used in health research to compare groups (e.g., smokers vs non-smokers) and their risk of disease.
how does an OR work
OR compares the odds of an event happening in one group versus another.
Odds = number of people with the event ÷ number without the event.
When Are ORs Used?
Common in case-control and prospective studies.
how does rr work
RR compares the probability (risk) of an event between two groups:
𝑅𝑅 =
Riskintreatmentgroup (divided) Riskincontrolgroup
what are confidence intervals
A confidence interval (CI) provides a range around a point estimate (like a mean difference or risk ratio) that likely contains the true effect size in the population.
It reflects the precision or uncertainty of the estimate.
CI is a range of values around the point estimate, often called the margin of error.
What is null hypthesis testing
Assumes no real difference or effect exists between groups or conditions. Any observed difference is due to random chance.
What is null hypothsis significance testing
A method to decide whether to reject or retain the null hypothesis based on sample data.
The result is binary: either there is a significant difference or there is not.
uses p-value
interpret the p-value in supporting hypothesis
P-value close to 1: Strong evidence supporting the null hypothesis (no difference).
P-value close to 0: Strong evidence supporting the alternative hypothesis (a real difference exists).
The p-value does not measure the size or importance of an effect, only the probability that the observed data would occur if the null hypothesis is true.
what are type I errors
occurs when a statistical hypothesis test incorrectly rejects a true null hypothesis, leading to a false positive conclusion
What is a type II error
known as a false negative
occurs when a test fails to detect a true effect or difference that actually exists.
In simpler terms, it’s like missing a real signal or failing to reject a false null hypothesis.
what is a sample
Research studies usually test a sample, not the entire population.
We use results from the sample to make inferences about the population.
What is power in a study
Power is the chance that the study will detect a real difference if one exists.
