In a population of pregnant female, Hb is estimated on 100 women with standard detion of 1gm %. The standard error is:
The most common parameters of interest in health are mean (m) and propoion (p). They tend to vary from sample to sample, if we take repeated samples from a target population the sample means and propoion will have a gaussian or non-gaussian distribution, called sampling distribution. The sample means will tend to vary around a population standard detion, but this variability is now called standard error of mean (SEM). Similarly we can get a standard error of propoion. The larger the standard error, larger will be the variability and less is our confidence in the sample results. SE (mean) = Sample standard detion where 'n' = sample size [?]n SE (propoion) = [?]p(1-p) where 'p' = propoion, and 'n'= sample size [?]n In this question, we can apply the given information to the formula for calculation of Standard error of mean as: 1/10= 0.1(Square root of 100 is 10) Ref: Park's Textbook of Preventive and Social Medicine; 18th edition; Page-649
1
0.1
0.01
10