The population standard deviation for the lengths, in seconds, of the songs in an online database is 15 seconds. If we want to be 90% confident that the sample mean is within 4 seconds of the true population mean, what is the minimum sample size that should be taken?

Solve 3x-18=2y and 5x-6y=14 by elimination or substitution . show all !

The american academy of pediatrics wants to conduct a survey of recently graduated family practitioners to assess why they did not choose pediatrics for their specialization. provide a definition of the population, suggest a sampling frame, and indicate the appropriate sampling unit.

Which statement is true about a number and its additive inverse? a. their product is always one. b. their sum is always one. c. they are always reciprocals of each other. d. their sum is always zero.