Hypothesis testing using TI-84 calculator (T-test, Right tailed) скачать в хорошем качестве

Hypothesis testing using TI-84 calculator (T-test, Right tailed)

The average monthly cell phone bill was reported to be $50.07 by the U.S. Wireless Industry. A random sampling of a large cell phone company found the following monthly cell phone charges (in dollars): 55.83 49.88 62.98 70.42 60.47 52.45 49.20 50.02 58.60 51.29 At the 0.05 level of significance, can it be concluded that the average phone bill has increased? (Note: The value of the sample mean (x ≈ $56.11) and sample standard deviation (s ≈ $6.97) are calculated.) a) State the hypotheses. b) Find the critical value and state the number of degrees of freedom. c) Compute the test value. What is the P-value interval? d) Make the decision. e) Summarize the results.