Biostatistics I Flashcards
Systematic reviews and meta-analysis have the most _____ ____, in other words, you can trust the most. Next down the list is ____ _____ trials. Then ____ studies. Then ____ ____ studies.
Methodological rigor
Randomized controlled
Cohort
Case control
_____ _____ are factors that increase a persons risk for a disease.
Risk factors
What is a risk factor for cholera?
What is a risk factor for skin cancer?
What is a risk factor for heart disease?
Contaminated water
UV rays
High blood pressure
Define incidence
Define incidence rate
The number of new cases of the disease for a population.
Number of new cases divided by a specific time frame.
_____ _____ is the probability of encountering an event. It is the same as the incidence rate of the event in a particular group.
Absolute risk
_____ ____ measures the excess risk accounted for by exposure to a particular risk factor. This is calculated by subtracting the ____ ____ in the two populations.
Attributable risk
Attributable risk calculation:
Lifetime incidence (risk) of colon cancer with lynch = 80%
Lifetime incidence (risk) of colon cancer without lynch = 5%
Attributable risk = 80% - 5% = 75%
Relative risk (risk ratio) is the risk for a condition in one population ____ to another.
In other words, people with Lynch syndrome are 16 times more likely to develop colon cancer, then someone without lynch syndrome.
Compared
Example: lifetime incidence of colon cancer with Lynch = 80%
Lifetime incidence of colon cancer without lynch = 5%
Relative risk = 80/5 = 16
What is the 5 year incidence of MI in those with hypertension?
60/1000 = 6%
73 / (73 + 915) = 7.4%
What is the relative risk of people with hypertension for developing an MI?
3
The portion of the risk of a disease in the population that is due to exposure to a risk is ___ ____ ____.
Attributable risk percent
What is the attributable risk percent using this table:
100 ((0.06- 0.02) / 0.06) = 66%
_____ all current cases are all cases at a given time, new and old. It is dependent on incidence, and their average duration of the disease from time to diagnosis to time of cure or death.
Prevalence.
Incidence and prevalence both measure the ____ ____ of a disease.
Morbidity rate
The ____ ____ ____ is a measure of severity of a disease. The number of fatal cases, divided by the total number of people with the disease.
The case fatality rate
_______ is used to determine if there are significant differences between the means of two groups.
T-test
_____ is used to determine whether there are significant differences between the means of two or more independent groups
ANOVA
_____ is reported in studies the compare the means of two or more groups.
P-value
If the P value is <.04, this indicates that there is a less than ____ percent chance that the difference that they found is due to chance alone.
4
P values of _____ are considered statistically significant
<0.05
____ ____ indicates a range of values within which we believe that the true value lies along with the level of certainty.
Confidence intervals
95% Cl: 3.0 to 3.9 means….
If this study were repeated, we would estimate that 95% of the time the results would fall between 3 and 3.9 times as likely to have an injury for example.
If the confidence interval does not include one, this means that the results are ____ ___ in other words the P value is <.05
If the confidence interval includes one, the P value is >.05 and not ____ ____.
Statistically significant
Statistically significant
