Research Flashcards
(96 cards)
Alternate Hypothesis (Ha or H1)
Statement that population parameter has a value different from null hypothesis
Accepted when null hypothesis is rejected
Null Hypothesis (Ho)
The Statistical Hypothesis
Statement that the value of a population parameter (mean, proportion or correlation coefficient) is equal to a claimed value
Tested statistically by interferential statistics
Independent Variable
What caused or influenced dependent variable
What is controlled or manipulated
Dependent Variable
The response or outcome
Caused by effect of independent variable
P-Value
Probability a statistical result happened by chance
If smaller than alpha level, null hypothesis is rejected
Alpha Level
The significance level
Probability of rejecting the null hypothesis or chance of Type I error
Often a = 0.05 or 0.01
Type I Error (Alpha Error)
Wrongly decide to reject null hypothesis
Conclude there is a difference or relationship when there is not
If alpha = 0.01, there is 1% chance of this error
A false positive finding
Type II Error (Beta Error)
Wrongly decide not to reject null hypothesis
Conclude no difference or relationship when there is one
A false negative finding
Statistically Significant
Small probability the difference or relationship between groups/variables happened by chance
Statistical Power
Chance a statistical test will lead to rejecting a false null hypothesis (find a statistically significant result)
Effect Size (ES)
Measure of magnitude of difference or relationship between treatments/variables
Larger ES = Greater chance to be statistically significant
Effect Size Index
Represents ES using standardized value
Difference between 2 groups divided by standard deviation of 1 group
TREATMENTmean - CONTROLmean / TREATMENTsd or CONTROLsd
< 0.1 = trivial effect
0.1-0.3 = small effect
0.3-0.5 = moderate effect
> 0.5 = large effect
Minimally Clinically Important Difference (MCID)
Minimally clinically significant difference (MCSD)
Smallest difference considered worthwhile and warrant change in patient management
Minimal Detectable Change (MDC)
Minimal Detectable Difference (MDD)
Minimum detectable change in patient condition beyond threshold of measurement error
Smallest difference or change that is statistically significant
Standard error of measurement (SEM) is used to determine this amount
Parameter
Numerical measurement describing population characteristic
Greek letters
Mu for mean
Sigma for std dev
Statistic
Numerical measurement describing characteristic of a sample
English letters
x or M for sample mean
s for std dev
Forest Plot (Blobbogram)
Used in meta-analysis
Results of individual studies and cumulative summary of all studies
Square on Horizontal Line: Estimate of measure of effect (odds ratio, relative risk)
Line Width: Confidence interval
Square Area: Study’s weight in the meta-analysis
Diamond on Horizontal Line: Estimate of cumulative effect
Vertical Line: No effect or null value
External Validity
Degree results are generalizable to populations or circumstances outside of study Threats: Treated specific type of subjects Place (setting) of study Time (history) of study
Internal Validity
Degree intervention caused outcome Degree independent variable caused dependent variable Threats: History Maturation Attrition Testing Instrumentation Regression towards the mean
Hawthorne Effect
Unstated subject experiences change from being in study
Change of behavior due to being observed or studied
Placebo Effect
Inactive treatment causes improvement because patient has expectation it will help
Quasi-Experimental Design
Design without control group, randomization, or both
One-Group Pretest-Posttest Design
Measurements on one group before and after
Time is independent variable
One-Way Repeated Measures Design Over Time
Measurements on one group at multiple prescribed time intervals
Intervention may be done once or repeated