What conditions are necessary in order to use the z-test to test the difference between two population means? select all the necessary conditions below. a. each population has a normal distribution with a known standard deviation. b. the samples are paired. c. the samples must be independent. d. the samples must be randomly selected?

Which of these people has balanced their checkbook correctly? oa. gary: the balance in his check register is $500 and the balance in his bank statement is $500. b. gail: the balance in her check register is $400 and the balance in her bank statement is $500. c. gavin: the balance in his check register is $500 and the balance in his bank statement is $510.

[10 points, algebra 2-simplifying complex fractions]according to my answer key the restrictions are -1 and 4. but why not positive 1?

Does the point (1, sqrt 7) lie on circle shown.