Based on Experiment 1, why was it important that all pots received the same volume of water?
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12 questions
Based on Experiment 1, why was it important that all pots received the same volume of water?
Experiment 1. A botany student tested how soil pH affects the growth of tomato seedlings. She prepared four identical pots with sterile potting soil, watered each with the same volume of water buffered to a specific pH, and recorded the seedling height after days under identical light and temperature.
| Pot | Soil pH | Height after 14 days (cm) |
|---|---|---|
| 1 | 4.5 | 3.2 |
| 2 | 5.5 | 7.1 |
| 3 | 6.5 | 9.4 |
| 4 | 7.5 | 5.8 |
In Experiment 1, what is the independent variable?
Across all three experiments, which one best supports a CAUSAL claim about the independent variable's effect on the dependent variable?
Based on Experiment 2, what specific change would strengthen the design as a test of the causal effect of rainfall on ring width?
Based on Experiment 2, in which year did the trees grow rings widest, and how does that year's rainfall compare?
Experiment 3. A clinical team compared two methods for measuring blood glucose: a finger-stick monitor (Method A) and a continuous-glucose sensor patch (Method B). Both methods were used on the same volunteers, and each volunteer's measurement was repeated times by each method. Average readings (mg/dL) for each volunteer were compared.
Which of the following is the most important reason both methods were used on every volunteer?
Experiment 2. An environmental scientist studied how tree-ring width varies with rainfall in the year the ring grew. She sampled trees from a single forest, measured ring widths for different years, and looked up that year's total rainfall.
| Year sampled | Total rainfall (cm) | Average ring width (mm) |
|---|---|---|
| 1991 | 38 | 2.1 |
| 1995 | 52 | 3.0 |
| 2003 | 71 | 4.4 |
| 2010 | 65 | 4.0 |
| 2018 | 45 | 2.5 |
Which of the following best characterizes Experiment 2's design?
Based on Experiment 3, why did the team take repeated measurements per volunteer with each method?
Based on Experiment 3, suppose the team found that Method A reads about mg/dL HIGHER than Method B on every volunteer. What conclusion is best supported?
Based on Experiment 1, what factor was held constant across all four pots?
Based on Experiment 2, why might it be problematic to claim that 'more rainfall causes wider rings' from this study alone?
Based on Experiment 1, what additional trial would most help refine the conclusion about the optimal pH for tomato seedling growth?