Question 9

Question 9 1 out of 5 points The Colgate company believes is toothpaste is more effective than its leading rival, Aim, in ghting tooth decay. A small scale clinical trial was held with 30 patients using Colgate and 21 using Aim. The results showed mat die mean and varianoe of [he number of cavities 'for Colgate was 10.2 and 9.85, respectively, with 'le resuhs 'for Aim being 1 1.4 and 8.42. It is assumed that the population varianoes are the same and the distribution of the number of cavities for bod-I groups closely approximates a normal distribution. Use alpha = 0.05. 1. If 'le hypotheses are to be written in die form ofthe average o'fAim minus d1e average of Colgate, what is the direction of d1e alternative hypothesis used to test Colgane's belief. Type the letters ggreaher than), ge (greater than or equal to], It (less than), le(less than or equal to} or he (not equal to] as appropriate in the box. [a] 2. Determine d1e standard error 'for die difference between means, reporting your answer to [tree decimal places.[b] 3. Calculate the test statistic, reporting your answer to two decimal places. [c] 4. Is the null hypothesis rejected for this test? Type yes or no.[d] 5. Regardless of your answer for 4, ifthe null hypolhesis was rejected, can we conclude that Colgate's belief is valid at die 5% level of signicance? Type yes or no.[e]