"This charpter explain about confidence intervals for mean(σ know or n≥30),confidence intervals for mean(σ unknow or n<30),confidence intervals and simple size for proportions and confidence intervals for variances and standard deviation 1. confidence intervals for mean(σ know or n≥30) - This material explains about calculate the mean in interval by n equal and greater than 30 2. confidence intervals for mean(σ unknow or n<30) - This material explains about calculate the mean in interval by n less than 30 3. confidence intervals and simple size for proportions - This material explains about calculate the proportion in interval 4. confidence intervals for variances and standard deviation - This material explains about calculate the variance and standard deviation in interval "