There are two major cell phone providers in the Colorado Springs, Colorado, area, one called HTC and the other Mountain Communications. We want to investigate whether there is a difference in the proportion of times a call is successful. During a one-week period, 500 calls were placed at random times throughout the day and night to HTC. 450 of the calls were successful. A similar one-week study with Mountain Communications showed that 352 of 400 calls were successful. At the .01 significance level, is there a difference in the percent of time that cell phone connections are successful? For calculations, assume HTC is the first sample.a. Pc =b. The test statistic is:c. Accept or reject the null?