1. A student dissolves 50 g of KNO₃ in 100 g of water at 40°C. Based on Figure 1, the resulting solution would be best described as:
2. A city tested a new bus-lane policy intended to reduce commute times. Commute times (minutes) were recorded for 30 randomly selected bus riders one week before implementation and for 30 bus riders one week after. The riders before and after were not necessarily the same individuals. Weather conditions differed: the “after” week had heavier rain on most days.
Table 1 shows the mean commute times. The author concluded: “The bus-lane policy increased commute times.”
Which of the following is a flaw in the author’s reasoning?
3. Suppose a new survey of the Milky Way's halo reveals a vast population of billions of rogue planets and brown dwarfs, totaling 5 times the mass of all visible stars. This finding would strictly support the hypothesis of:
4. Ecologists investigated whether adding artificial nest boxes increases the number of breeding pairs of a bird species in urban parks. Four parks received 20 nest boxes each (Box parks) and four similar parks received none (No-box parks). Breeding pairs were counted in spring before installation (Year 0) and the next spring (Year 1). One Box park underwent tree removal between years.
Authors concluded: “Nest boxes caused the population increase observed in Year 1.”
Which of the following is a flaw in the author's reasoning?
5. Engineers evaluated whether a new tire tread (Tread N) improves braking distance on wet pavement. Ten cars of the same model were tested on a closed track. Each car performed two braking trials from 60 km/h: one with standard tires and one with Tread N. Testing occurred on two different days; Day 2 had heavier rainfall.
The authors concluded: “Tread N reduces wet braking distance under rainy conditions.”
Which statement best evaluates the validity of the author's conclusion?
6. A study examined whether listening to instrumental music improves memory recall. Forty students were assigned to either Music or Silence during a 15-minute study period. Students then completed a 30-word recall test. Researchers also recorded whether students reported being “well-rested” (≥7 hours sleep) or “tired” (<7 hours).
The authors concluded: “Instrumental music significantly improves memory recall for students.”
The conclusion that the authors’ claim is:
7. A lab tested whether a disinfectant (Solution D) reduces bacterial growth on countertops. Identical countertop squares were inoculated with bacteria and then treated with either Solution D or water (Control). After 4 hours, technicians counted colony-forming units (CFU). The experiment was repeated at two room humidities.
Based on the data, which conclusion is most strongly supported?
8. Meteorologists examined whether a city’s new reflective roof policy reduced summer electricity demand. Monthly mean daytime temperature and total electricity use were recorded for June–August in the year before the policy (Year A) and the year after (Year B). No other energy policies were reported, but Year B had a cooler summer.
The authors concluded: “Reflective roofs reduced summer electricity demand.”
Which statement best evaluates the validity of the author's conclusion?
9. Atmospheric pressure is defined as the force exerted by the weight of the air above a given point. Based on Figure 2, which of the following statements best explains why atmospheric pressure decreases with altitude?
10. Researchers assessed the impact of caffeine on memory retention. Table 12 shows memory scores with varying caffeine doses. Which statement best evaluates the author's conclusion that caffeine improves memory?
11. Researchers conducted an experiment to test the effect of temperature on enzyme activity. Table 1 shows enzyme activity levels at different temperatures. According to the data, which of the following can be concluded?
12. At terminal velocity, the drag force on an object is exactly equal to the object's weight (gravitational force). Based on Study 1, what is the ratio of the drag force acting on N\=2 filters at terminal velocity to the drag force acting on N\=4 filters at terminal velocity?
13. According to the passage, why did adding 1.00 mole of sucrose have a smaller effect on the boiling point of the water than adding 1.00 mole of NaCl?
14. A survey recorded the number of hours students studied per week and their exam scores. Figure 2 shows a scatter plot of study hours versus exam scores. Which conclusion is most strongly supported by the data?
15. A hydrology study measured nitrate concentration in a stream upstream and downstream of a farm. Samples were taken on three dates. Between Date 1 and Date 2, the farm applied fertilizer. Between Date 2 and Date 3, a large storm occurred.
Based on the data, which conclusion is most strongly supported?
16. A team analyzed the relationship between sleep duration and cognitive performance. Table 4 shows cognitive scores for different sleep durations. Which statement accurately describes the relationship?
17. A biology class investigated whether a certain wavelength of light affects plant height. Students grew seedlings under either red LEDs or blue LEDs for 14 days. Each group used the same soil and watering schedule, but the red-LED shelf was closer to a window and received some additional sunlight.
The authors concluded: “Red light causes greater seedling growth than blue light.”
Which statement best evaluates the validity of the author's conclusion?
18. An astronomy team measured the brightness of a variable star over 6 nights using the same telescope. Brightness was recorded as apparent magnitude (lower magnitude = brighter). Cloud cover was noted each night.
The authors concluded: “The star dimmed on Nights 3 and 4 due to intrinsic stellar variability.”
Which statement best evaluates the validity of the author's conclusion?
19. A medical device company tested whether a new wristband reduces tremor amplitude in patients with essential tremor. Twelve patients wore the wristband for 1 hour on Day 1 (device OFF) and Day 2 (device ON). Tremor amplitude (arbitrary units) was measured during a standardized task. Day 2 measurements were always taken after Day 1.
The authors concluded: “The wristband reduces tremor amplitude.”
Which statement best evaluates the validity of the author's conclusion?
20. An experiment assessed the impact of sugar intake on energy levels. Table 6 shows energy levels after consuming different sugar amounts. Which conclusion is supported by the data?
21. An experiment tested the effect of caffeine on reaction time. Table 3 displays average reaction times before and after caffeine consumption. What can be concluded from the data?
22. A team studied the influence of temperature on bacterial growth. Table 10 lists growth rates at different temperatures. What conclusion is most strongly supported by the data?
23. An analysis was conducted to assess the effect of vitamin C on immune response. Table 14 lists immune response levels with different vitamin C doses. Which conclusion is best supported by the data?
24. Consider the data point in Figure 1 where the resistance is 24 Ω and the current is 0.5 A. Does this data point support the equation $V = I \times R$ if the voltage was held at 12 V?
25. A scientist claims that Strain B enzymes are "thermophilic" (heat-loving) compared to Strain A enzymes. Do the results in Figure 1 support this claim?
26. Based on the data in both studies, which of the following combinations of light intensity and relative humidity would likely produce the highest overall transpiration rate for a Spathiphyllum plant?
27. Based on the passage introduction, when Parachute X reaches its terminal velocity of 2.8 m/s, what is the relationship between the gravitational force (Fg) and the drag force (Fd)?
28. Based on Figure 1, which color of light resulted in the lowest rate of photosynthesis, and what is the most likely biological explanation?
29. A student hypothesizes that any pitch angle greater than 15° will result in a lower power output than the output achieved at exactly 15°. Do the results of Study 2 support this hypothesis?
30. A student dissolves 50 g of KNO₃ in 100 g of water at 40°C. Based on Figure 1, the resulting solution would be best described as:
31. Which of the following statements best explains the trend for the Mouse in Study 1 (Figure 1)?
32. A geophysicist claims that the "shadow zone" (an area where no seismic waves are detected) occurs because P-waves are bent (refracted) by the sudden change in density at the core-mantle boundary. Do the data in Figure 1 and Figure 2 support the idea that there is a sudden change in material properties at this boundary?
33. A student hypothesized that increasing the concentration of NaHCO₃ indefinitely will continue to increase the rate of photosynthesis linearly. Do the results of Study 3 support this hypothesis?
34. A study evaluated the effect of exercise on heart rate. Table 5 lists average heart rates of subjects before and after a 30-minute workout. Which of the following is a valid conclusion?
35. An experiment measured the pH of a solution as different substances were added. Table 2 shows the pH changes when substance X was added. Which statement best evaluates the author's conclusion that substance X is a strong acid?
36. A chemist investigated how temperature affects the rate of a reaction that produces gas. The same concentrations of reactants were used each time. The chemist measured the time required to produce 50 mL of gas at three temperatures.
Based on the data, which conclusion is most strongly supported?
37. A psychology experiment tested whether a brief mindfulness session reduces test anxiety. Sixty students were randomly assigned to either 10 minutes of guided mindfulness or quiet sitting. Anxiety was rated (0–100) immediately before and immediately after the session.
Based on the data, which conclusion is most strongly supported?
38. A sports scientist tested whether caffeine improves sprint performance. Sixteen athletes completed a 200 m sprint after consuming either caffeine (3 mg/kg) or a placebo in a crossover design one week apart. However, all athletes received caffeine in Week 1 and placebo in Week 2. Weather differed: Week 1 had a tailwind; Week 2 had no wind.
Which statement best evaluates the validity of the author's conclusion that “Caffeine caused faster sprint times”?
39. A field study assessed whether a pesticide (PX) reduces aphid counts on soybean plants. Two adjacent plots were used: Plot 1 was sprayed with PX; Plot 2 was not sprayed. Aphids per plant were counted weekly for 4 weeks. During Week 3, a heavy rainstorm occurred that washed insects from leaves.
The authors concluded: “PX caused the decline in aphid numbers.”
Which statement best evaluates the validity of the author's conclusion?
40. A materials scientist tested whether adding carbon fibers increases the tensile strength of a polymer. Samples were prepared with 0%, 5%, or 10% carbon fiber by mass. For each composition, five samples were pulled until failure and the mean tensile strength was recorded.
According to the data, which of the following can be concluded?
41. A physiology study tested whether drinking a caffeinated beverage increases reaction speed. Twenty adults completed a computerized reaction-time task on two days. On Day 1 they drank a caffeinated drink; on Day 2 they drank a caffeine-free drink. The order was not counterbalanced: all participants received caffeine on Day 1 and decaf on Day 2. Reaction time (ms) was measured 30 minutes after drinking.
Table 1 reports the mean reaction times. The author concluded: “Caffeine decreases reaction time (improves speed).”
Which of the following is a flaw in the author’s reasoning?
42. A nutrition study tested whether drinking green tea lowers blood glucose after a meal. Twenty adults were randomly assigned to drink either green tea or water with an identical carbohydrate meal. Blood glucose (mg/dL) was measured at baseline and 60 minutes post-meal.
According to the data, which of the following can be concluded?
43. A geology team tested whether adding water to sand increases its angle of repose (the steepest stable slope). Sand was poured into a pile under controlled conditions. Trials were conducted with dry sand and with sand containing 5% water by mass.
Based on the data, which conclusion is most strongly supported?
44. An environmental engineer tested whether a filter (Filter Q) removes lead from water. A water sample containing dissolved lead was split into two equal portions. One portion was passed through Filter Q; the other was not filtered. Lead concentration was measured before and after.
Based on the data, which conclusion is most strongly supported?
45. A public health team evaluated whether installing bike lanes increases cycling. Two streets received protected bike lanes (Lane streets) and two similar streets did not (No-lane streets). Cyclists were counted during morning rush hour for one week before installation and one week after installation. After installation, a citywide “Bike Week” campaign occurred.
Which of the following is a flaw in the author's reasoning if they conclude: “Protected bike lanes caused the increase in cycling after installation.”
46. Researchers tested whether a new fertilizer (Fert-X) increases tomato yield. Twenty greenhouse benches (each bench held 10 identical tomato plants) were randomly assigned to either Fert-X or a standard fertilizer (Control). All benches received the same watering schedule and light cycle. After 8 weeks, researchers measured mean fruit mass per plant (g) for each bench and recorded greenhouse zone (East or West). The researchers noticed the West zone ran ~2°C warmer than the East zone due to a vent.
The authors concluded: “Fert-X causes higher tomato yield than the standard fertilizer.”
Which statement best evaluates the validity of the author's conclusion?
47. A neuroscience lab studied whether blue-light exposure before bedtime affects sleep onset latency (minutes to fall asleep). Twenty participants followed a fixed bedtime for 5 nights. On Nights 1–2, participants used a blue-light filter on their phones; on Nights 3–5, the filter was off. Participants also reported daily caffeine intake.
The authors concluded: “Turning off the blue-light filter causes people to take longer to fall asleep.”
Which statement best evaluates the validity of the author's conclusion?
48. Researchers explored the effect of music on concentration. Table 8 shows concentration scores with different music genres. What conclusion is best supported by the data?
49. Suppose a new survey of the Milky Way's halo reveals a vast population of billions of rogue planets and brown dwarfs, totaling 5 times the mass of all visible stars. This finding would strictly support the hypothesis of:
50. A geophysicist claims that the "shadow zone" (an area where no seismic waves are detected) occurs because P-waves are bent (refracted) by the sudden change in density at the core-mantle boundary. Do the data in Figure 1 and Figure 2 support the idea that there is a sudden change in material properties at this boundary?
51. Which of the following statements best explains the trend for the Mouse in Study 1 (Figure 1)?
52. A student hypothesized that increasing the concentration of NaHCO₃ indefinitely will continue to increase the rate of photosynthesis linearly. Do the results of Study 3 support this hypothesis?
53. Based on Figure 1, which color of light resulted in the lowest rate of photosynthesis, and what is the most likely biological explanation?