The p-value represents the probability of obtaining a test statistic at least as extreme as the one that was actually observed, assuming the null hypothesis is true. A confidence interval provides a range within which the population mean is likely to fall. The variance measures how far data points are spread out from the mean and is calculated as the sum of squared deviations from the mean divided by the sample size minus one. The coefficient of variation allows for more meaningful comparison of distributions with different magnitudes than just comparing standard deviations. The standard error of the sample mean represents the variability of the sample mean as an estimate of the true population mean.