Understanding Basic Statistics 6th Edition by Charles Henry Brase,Corrinne Pellillo Brase

تمرين 34

For all Hypothesis tests, please provide the following information:
(i) What is the level of significance State the null and alternate hypotheses.
(ii) Check Requirements What sampling distribution will you use What assumptions are you making What is the value of the sample test statistic
(iii) Find (or estimate) the P -value. Sketch the sampling distribution and show the area corresponding to the P -value.
(iv) Based on your answers in parts (i)-(iii), will you reject or fail to reject the null hypothesis Are the data statistically significant at level
(v) Interpret your conclusion in the context of the application.
Testing and Estimating m 1 - m 2 , s 1 and s 2 Unknown In the airline business. "on-time" flight arrival is important for connecting flights and general customer satisfaction. Is there a difference between summer and winter average on-time flight arrivals Let x 1 be a random variable that represents percentage of on-time arrivals at major airports in the summer. Let x 2 be a random variable that represents percentage of on-time arrivals at major airports in the winter. A random sample of n 1 = 16 major airports showed that
, with s 1 = 5.2%. A random sample of n 2 = 18 major airports showed that
, with s 2 = 8.6% (Reference: Statistical Abstract of the United States ).
(a) Does this information indicate a difference (either way) in the population mean percentage of ontime arrivals for summer compared to winter Use = 0.05.
(b)Find a 95% confidence interval for µ 1 µ 2.
(c) What assumptions about the original populations have you made for the methods used