以下对断裂力学的诞生与发展做出过重要贡献的有 。 A: Griffith B: Irwin C: Rice D: Prandtl
以下对断裂力学的诞生与发展做出过重要贡献的有 。 A: Griffith B: Irwin C: Rice D: Prandtl
Stefan Irwin, Marketing Manager at Classic Merchandise, is investigating response rates to scented and unscented direct mail catalogues. If the response rate for the scented catalogue (population 1) is higher, Mike will adopt the scented version. His staff randomly selects two samples of 200 each from the company’s customer database. One month after the 400 test catalogues were mailed, forty-five orders (twenty-five from the scented and twenty from the unscented) were received from the test catalogues. Assuming a = .01, Mike’s alternate hypothesis is ________________.
Stefan Irwin, Marketing Manager at Classic Merchandise, is investigating response rates to scented and unscented direct mail catalogues. If the response rate for the scented catalogue (population 1) is higher, Mike will adopt the scented version. His staff randomly selects two samples of 200 each from the company’s customer database. One month after the 400 test catalogues were mailed, forty-five orders (twenty-five from the scented and twenty from the unscented) were received from the test catalogues. Assuming a = .01, Mike’s alternate hypothesis is ________________.
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