A Confidence interval is a range of values that likely would contain an unknown population parameter. Confidence level refers to the percentage of probability, or certainty, that the confidence interval would contain the true population parameter when you draw a random sample many times. Confidence intervals are described broadly as tools for extracting necessary information about the data parameter. Populations and samples with more variability generate wider confidence intervals and sample Size. As noted in other readings the smaller the sample size the wider the intervals.