Statistical Analysis
CONFIDENCE INTERVAL
What is the confidence interval ?
Statisticians calculate the range (interval) in which we can be fairly sure (confident) the true value of your population of interest is represented by your sample means, not population mean.
The Goal of ci:
True estimation, in a range of sample mean the true value is the mean value if we had data for the population of interest.
Confidence interval:
Precision and confidence:
Example:
The mean HbA1c before treatment of a group of 100 patients with diabetes was 64 mmol/L. After treatment with Drug A, the mean dropped by 10 mmol/L.
Population/ diabetic patients
Variable/ HA1C
Sample mean/ 100 diabetic patient with mean HA1C before intervention 64mmol/L
intervention/ oral hypoglycemic drug
Sample mean/ HbA1C after treatment dropped by 10 mmol/L
Now, if our 95% confidence interval located between 4 and 16 so, the effect of oral hypoglycemic in reduction of HA1C in true value( true mean= mean of study population) 95% confidant between 4 and 16.
So, if we continuo to take more sample mean post intervention we are 95% confidant the mean of HA1C between 4 to 16.