Problem 1: The Brand A cellphone company claims that its phones have an almost the same lifespan as of the Brand B cellphone company. A test is conducted to validate whether the claim is true. 18 phones from Brand A and 24 phones from Brand B are chosen for testing, and it was found that the mean life for each is 32 and 35 months for Brand A and Brand B, respectively. The standard deviation for Brand A is 5 months while 7 months for Brand B. Test the hypothesis using a level of signicance of 1%