“It’s a draw,” according to two Australian researchers. “By age 25, up to 29% of all men and up to 34% of all women have some gray hair, but this difference is so small that it’s considered insignificant” (“Silver Threads Among the Gold: Who’ll Find Them First, a Man or a Woman?” Family Circle).
a. If 1000 men and 1000 women were involved in this research, construct a 95% confidence interval to estimate the true difference.
b. Does the confidence interval found in part a indicate that the difference is significant? Explain.