why does a paired t test result in better variance? why do paired t test results better for a covariance why does paired t-test result in better variance why does a paired t test results in a better variance? why does a paired test result in better variance do paired t tests have more or less variance? why do paired t-tests have better variance why do paired t tests lead to better variance? why does an unpaired t test result in a better variance why does a paired t test result in better variance? why do unpaired t-tests result in better variance why do paired tests always have better correlation than unpaired tests? why does a paired t test result in better variance? why paired t test results better why is paired analysis better than unpaired why do paired t-tests result in better variance why does paired testing lead to better variance? which test has the best variance, paired variance, and unpaired variance? do pairs of tests result in better correlations why do paired tests produce better variance?