Lena wants to grow corn on the farm she just bought. The previous farmer grew corn...

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Lena wants to grow corn on the farm she just bought. The previous farmer grew corn for several decades and kept detailed records of his crop production each year. These records include the amount of sunlight, the amount of rain, the average yield, and other such figures. In an effort to help Lena out, the previous farmer compares his records of using two popular fertilizers: Earthy and SunX. He pulls his records for the 8 seasons he used Earthy on his corn and the records for the 8 seasons that he used Sunx on his corn. He uses these records to compare the average corn yield for the 8 seasons that he used Earthy to the average corn yield for the 8 seasons that he used Sunx. If applicable, he will recommend the better fertilizer to Lena. (a) First choose whether the procedure described above is an observational study or a designed experiment. Then further categorize the procedure by choosing the correct type of observational study or designed experiment. Observational study O prospective O retrospective Designed experiment O double-blind O completely randomized ? (b) Which one of the following best describes the explanatory (independent) and response (dependent) variables? O The explanatory variable is the brand of fertilizer and the response variable is the sunlight. O The explanatory variable is the brand of fertilizer and the response variable is the average corn yield. O The explanatory variable is the average corn yield and the response variable is the brand of fertilizer. O The explanatory variable is the sunlight and the response variable is the average corn yield. (c) Suppose there is a significant difference in the average yields between the corn crops grown with Earthy and the corn crops grown with Sunx. Would the farmer be well-justified in claiming that the difference in the average yields was caused by the choice of fertilizer? Choose the best answer below. O No. The farmer has only found evidence to support a claim of an association between the average yield and the choice of fertilizer. No. There is no procedure, however well-designed, that can give evidence to support a claim of a cause-and-effect relationship. Yes. Because the procedure used data from past growing seasons, there can be no error in the measurements. So, a cause-and-effect relationship is well-justified. Lena wants to grow corn on the farm she just bought. The previous farmer grew corn for several decades and kept detailed records of his crop production each year. These records include the amount of sunlight, the amount of rain, the average yield, and other such figures. In an effort to help Lena out, the previous farmer compares his records of using two popular fertilizers: Earthy and SunX. He pulls his records for the 8 seasons he used Earthy on his corn and the records for the 8 seasons that he used Sunx on his corn. He uses these records to compare the average corn yield for the 8 seasons that he used Earthy to the average corn yield for the 8 seasons that he used Sunx. If applicable, he will recommend the better fertilizer to Lena. (a) First choose whether the procedure described above is an observational study or a designed experiment. Then further categorize the procedure by choosing the correct type of observational study or designed experiment. Observational study O prospective O retrospective Designed experiment O double-blind O completely randomized ? (b) Which one of the following best describes the explanatory (independent) and response (dependent) variables? O The explanatory variable is the brand of fertilizer and the response variable is the sunlight. O The explanatory variable is the brand of fertilizer and the response variable is the average corn yield. O The explanatory variable is the average corn yield and the response variable is the brand of fertilizer. O The explanatory variable is the sunlight and the response variable is the average corn yield. (c) Suppose there is a significant difference in the average yields between the corn crops grown with Earthy and the corn crops grown with Sunx. Would the farmer be well-justified in claiming that the difference in the average yields was caused by the choice of fertilizer? Choose the best answer below. O No. The farmer has only found evidence to support a claim of an association between the average yield and the choice of fertilizer. No. There is no procedure, however well-designed, that can give evidence to support a claim of a cause-and-effect relationship. Yes. Because the procedure used data from past growing seasons, there can be no error in the measurements. So, a cause-and-effect relationship is well-justified.