Two catalysts may be used in a batch chemical process. twelve batches were prepared using catalyst 1, resulting in an average yield of 85 and a sample standard deviation of 3. fifteen batches were prepared using catalyst 2, and they resulted in an average yield of 92 with a standard deviation of 2. assume that yield measurements are approximately normally distributed with the same standard deviation.
(a) is there evidence to support a claim that catalyst 2 produces a higher mean yield than catalyst 1? use α = 0.01.
(b) find a 99% confidence interval on the difference in mean yields that can be used to test the claim in part (a).

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Electron equations of the given changes are as follow,a)                              cu      →      cu⁺²  + 2e⁻b)                              mg⁺²  +  2 e⁻      →      mgc)                              cl⁻    →      cl  +  1e⁻d)                              s  +  2 e⁻    →      s²⁻e)                                o²⁻      →      o  +  2 e⁻f)                              p  +  3 e⁻    →      p³⁻g)                              fe²⁺    →      fe³⁺  + 1 e⁻h)                              s²⁻    →      s⁴⁺  +  6 e⁻