Cancer patients. Cancer.org reports that 30% of American women cancer patients have breast cancer.

An analysis was conducted to determine whether the report is true and a z-score of 3.12 is found.

a) Explain what the z-statistic means in this context.

b) Look up the 0.1 upper critical value for a two-tailed z-statistic, and state your conclusion about the test.

c) Why did you probably not need to look up the critical value in part b to reach your conclusion?