A manufacturer of small engines concerned with the issue of noise pollution developed a new engine that would, it was hoped, be quieter than the standard model. Forty-one of the new models were tested for noise level and compared with 65 of the standard models. The results are given below with noise measured in decibels. (The higher the decibel is, the higher the noise level is ). Assume that the noise levels of both the standard and the new model engines are normally distributed. Sample Size Sample Mean (Decibels) Sample Standard deviation (decibels)
Standard Model 65 84 11.6
New Model 41 72 9.2
At 5 % level of significance, test the claim (using test of hypothesis procedure) that the new model is significantly quieter than the old model. Use P-value method. Show all four steps and showcompletework. UseP-ValueMethod.