Scientific Reasoning Practice Questions

1. A researcher is investigating the effect of light intensity on the rate of photosynthesis in a plant. They set up four experiments, each with the same plant species and growth conditions, but with different light intensities: 100 lux, 500 lux, 1000 lux, and 2000 lux. They measure the rate of oxygen production in each experiment as an indicator of the rate of photosynthesis. Which of the following graphs would best represent the relationship between light intensity and the rate of photosynthesis?

2. A scientist is investigating the effect of temperature on the rate of a chemical reaction. They set up an experiment with 5 reaction vessels, each maintained at a different temperature (10°C, 20°C, 30°C, 40°C, and 50°C). They measure the rate of the reaction in each vessel and record the data. Which of the following is the best way for the scientist to analyze the data and determine the relationship between temperature and reaction rate?

3. A biologist is studying the effect of different nutrient concentrations on the growth of a plant species. They plant the same number of seedlings in four different nutrient solutions and measure the height of the plants after a fixed time. Which of the following is the best way to analyze the data and determine the effect of nutrient concentration on plant growth?

4. A researcher is investigating the effect of a new fertilizer on the growth of tomato plants. They plant 20 tomato seedlings and divide them into 4 groups of 5 plants each. They apply different concentrations of the fertilizer to each group and measure the height of the plants after 4 weeks. The data they collect is as follows: Group 1 (control, no fertilizer): Plant heights (cm): 25, 28, 30, 27, 29 Group 2 (low fertilizer concentration): Plant heights (cm): 32, 35, 33, 36, 34 Group 3 (medium fertilizer concentration): Plant heights (cm): 40, 42, 38, 41, 39 Group 4 (high fertilizer concentration): Plant heights (cm): 45, 47, 43, 46, 44 Based on the data, which of the following conclusions can the researcher draw about the effect of the fertilizer on tomato plant growth?

5. A biologist is studying the effect of temperature on the rate of photosynthesis in a plant species. They set up four growth chambers, each with the same light intensity and nutrient conditions, but with different temperatures. After a fixed time, they measure the rate of oxygen production (a proxy for photosynthesis rate) in each chamber. Which of the following is the best way to analyze the data and determine the effect of temperature on the rate of photosynthesis?

6. A biologist is studying the effect of light intensity on the growth of a plant species. They set up four growth chambers, each with the same soil, water, and nutrient conditions, but with different light intensities. After a fixed time, they measure the height of the plants in each chamber. Which of the following is the best way to analyze the data and determine the effect of light intensity on plant growth?

7. A researcher is studying the effects of a new fertilizer on the growth of tomato plants. They plant 24 tomato seedlings and divide them into three groups of 8. One group receives the new fertilizer, one group receives a different fertilizer, and the control group receives no fertilizer. After 4 weeks, the researcher measures the height of each plant. The researcher wants to determine if there is a statistically significant difference in the height of the plants between the three groups. Which statistical test would be most appropriate for the researcher to use?

8. A researcher is studying the effects of a new drug on the survival of cancer cells in a petri dish. They expose the cancer cells to different concentrations of the drug and measure the percentage of cells that survive after 48 hours. The researcher wants to determine the half-maximal effective concentration (EC50) of the drug, which is the concentration at which 50% of the cells are killed. Which of the following methods would be most appropriate for the researcher to use to calculate the EC50?

9. A researcher is investigating the effect of a new fertilizer on the growth of tomato plants. They set up an experiment with two groups: one group receives the new fertilizer, and the other group (the control) receives no fertilizer. After 4 weeks, they measure the height of each plant. Which statistical test should the researcher use to analyze the data and determine if there is a significant difference in plant growth between the two groups?

10. A researcher is investigating the effect of a new fertilizer on the growth of tomato plants. They set up an experiment with two groups: one group receives the new fertilizer, and the other group (the control) receives no fertilizer. After 4 weeks, they measure the height of each plant. Which statistical test should the researcher use to analyze the data and determine if there is a significant difference in plant growth between the two groups?