Final answer:
The bakery uses a random assignment of numbers to loaves of bread, a random number generator to select loaves for different preservative amounts, and comparison of shelf life to assess the impact of new preservatives. Randomization and control are key aspects of the experimental design to ensure reliable results.
Step-by-step explanation:
The experimental design used by the bakery to assess the impact of a new preservative on the shelf life of its bread involves three key steps. The first step is the random assignment of numbers 001 to 150 to each of the 150 loaves of bread to ensure that any selection bias is minimized. This is crucial for obtaining reliable results that can be generalized to the broader population of bread loaves.
In the second step, a random number generator is used to select 50 loaves for each of the three levels of preservative: 0.5 grams, 1 gram, and none. This random selection is important to ensure that each group is representative of the whole sample and that the only expected difference between groups is the amount of preservative they receive.
The third step is to compare the shelf life of the bread across the different amounts of preservative added. The shelf life is the dependent variable and is measured for each loaf to determine the efficacy of the preservatives. Having experimental units within each treatment group allows the bakery to control for other variables that might affect the results, ensuring that the observed effects on shelf life can reasonably be attributed to the preservatives.
Overall, this experimental setup is designed to create comparable and controlled conditions that can highlight the effects of preservatives on bread shelf life. It emphasizes the importance of randomization and control in scientific experimentation, which is pivotal in drawing valid conclusions.