In 2010 polls indicated that 73% of Americans favored mandatory testing of students in public schools as a way to rate the school. This year in a poll of 1,000 Americans 70% favor mandatory testing for this purpose. Has public opinion changed since 2010? We test the hypothesis that the percentage supporting mandatory testing is less than 73% this year. The p -value is 0.015. Which of the following interpretation of this p -value is valid? The probability that Americans have changed their opinion on this issue since 2010 is 0.015. If 73% of Americans still favor mandatory testing this year, then there is a 1.5% chance that poll results will show 70% or fewer with this opinion. There is a 1.5% chance that the null hypothesis is true.