On November 1, 2001, EPA adopted new standards for arsenic in drinking water equal to a maximum 10 ppb. Every few months, an environmental engineer working with the Western UP Health Department collects samples from a local drinking water utility to see if the data demonstrate that the mean concentration of Arsenic exceeds the 10 ppb standard. Assume that sample values are normally distributed about the true mean. Suppose that the most recent set of 7 sample values yielded a sample average of 14.36 ppb and a sample standard deviation of 4.76 ppb. A. Specify the appropriate null and alternative hypotheses to demonstrate that the mean concentration of arsenic exceeds the standard or 10 ppb.
B. What is the rejection region for a 1% test?
C. What do you conclude for this data set?

Janice determined there were 10 possible outcomes when tossing two coins and spinning a spinner numbered 1 through 6. what is the correct number? what might have been janice's error?

What is the gcf of 20c^3-5c^4+30c^6

(20 points) a bank has been receiving complaints from real estate agents that their customers have been waiting too long for mortgage confirmations. the bank prides itself on its mortgage application process and decides to investigate the claims. the bank manager takes a random sample of 20 customers whose mortgage applications have been processed in the last 6 months and finds the following wait times (in days): 5, 7, 22, 4, 12, 9, 9, 14, 3, 6, 5, 15, 10, 17, 12, 10, 9, 4, 10, 13 assume that the random variable x measures the number of days a customer waits for mortgage processing at this bank, and assume that x is normally distributed. 2a. find the sample mean of this data (x ě…). 2b. find the sample variance of x. find the variance of x ě…. for (c), (d), and (e), use the appropriate t-distribution 2c. find the 90% confidence interval for the population mean (îľ). 2d. test the hypothesis that îľ is equal to 7 at the 95% confidence level. (should you do a one-tailed or two-tailed test here? ) 2e. what is the approximate p-value of this hypothesis?