Justifying Claims: Difference of Two Means Practice Test

A hospital compares mean length of stay (days) for patients receiving a new discharge protocol (New) versus the old protocol (Old). A 98% confidence interval for $\mu_{New}-\mu_{Old}$ is $(-1.9,\ -0.4)$. The hospital claims the new protocol reduces mean length of stay. Is the claim supported by the interval?

A teacher compares mean quiz scores (percent) between a class that used practice quizzes (P) and a class that did not (N). A 95% confidence interval for $\mu_P-\mu_N$ is $(-4,\ 9)$. The teacher claims using practice quizzes increases the mean quiz score. Is the claim supported by the interval?