The World Values Survey asks if homosexuality is justifiable, on a scale from 1 (“never”) to 10 (“always”).

In 1981–1984 surveys, the 2325 respondents in the United States had a mean response of 2.4 and standard deviation of 2.3.

In 2010–2014 surveys, the 2232 U.S. respondents had a mean of 5.4 and standard deviation of 3.4.

A report about the results stated, “The mean tolerance level for homosexuality was 3 units higher in 2010–2014 than in 1981–1984. If the true means were equal, a difference of this size could be expected less than 0.01% of the time. For samples of this size, 95% of the time one would expect this difference in means to be within 0.2 of the true value.”

(a) Explain how this conclusion refers to the results of a

(i) confidence interval, (ii) significance test.

(b) Describe how you would explain the results of the study to someone who has not studied inferential statistics.