Analyzing Data and Drawing Conclusions

Gerald performed an experiment to determine if photosynthesis was affected by the amount of light that a plant received. The data from his experiment are shown in the table below. Which format should he use to present his data?

A. Bar graph

For a conclusion to be accepted by the scientific community, the data must be accurate, free of error, and...

A. Reproducible

Why are graphs useful when interpreting data?

A. They make trends in the data easier to see.

A class was performing an experiment to discover the pH values of some common household substances. The results of three groups are shown in the table below. Which statement best describes evidence that Group 3's data are less valid than the data for the other two groups.

B. Group 3's pH value for vinegar is much higher than the values of the other two groups.

The pH scale measures the acidity or the basicity of a solution. Solutions that have a pH below 7 are acids. Solutions that have a low pH are more acidic than solutions that have a higher pH. The graph below shows the pH of four common fruit juices. A student studying acidity of juices did a taste test and determined that the orange juice was the sweetest juice and the lemon and lime juices were the sourest. Based on this information, which is the best inference the student could make about acidity?

B. Higher acidity causes juices to taste more sour.

Anjuli performed an experiment to determine the respiration rate of yeast. She determined this by measuring the amount of carbon dioxide CO2) that was produced. Then, she created the following graph. Her teacher suggested that she redraw her graph as a line graph. Why should she redraw the graph?

B. She was measuring rate of change.

Mario performed an experiment to determine if photosynthesis was affected by the amount of light that a plant received. The data from his experiment are shown in the table below. What could he have done to increase the validity of his data?

C. Add a 0 hours control.

What is the most appropriate way to present the data below?

C. Line graph

Francis was recording plant heights for an experiment. Each time that she took a measurement, she wrote it down. Then, she measured the plant again and compared the new measurement to the one that she had recorded in her notebook. What was she most likely trying to do?

C. Make the data more valid.

A scientist was measuring the effect of water temperature on dissolved oxygen in a local lake during the spring. The lake was experiencing increased algal growth due to runoff from a nearby cornfield. The scientist plotted his data in the graph below. The scientist concluded that the decrease in oxygen levels was caused by the increase in temperature. Which additional explanation is most likely correct?

C. The decrease in oxygen levels was also caused by the increased algal growth.

Ali hypothesized that increasing fertilizer would increase plant growth. Four groups of thirty similar plants were given 0 to 15 ml of fertilizer, as shown in the graph. The change in plant height for each group over a two-week period was averaged and recorded. What is the best conclusion based on this data.

C. The hypothesis was not supported; the data indicated that too much fertilizer can inhibit plant growth.

A geologist and a biologist performed an experiment together and examined the data. Each scientist formed a different conclusion. Both conclusions were supported by the evidence. How is this possible?

C. There can be alternate explanations for the same evidence.

What is the best definition of a conclusion?

D. An explanation that uses data to support or reject a hypothesis.

How can evidence from an experiment be explained in relationship to the hypothesis?

D. As a conclusion

Jake and Aisha conducted an experiment together to test the effects of fertilizer runoff on the amount of dissolved oxygen in a lake. They each created a graph from the results. Jake concluded that the runoff had little effect on the dissolved oxygen levels. What is the most likely reason that Jake and Aisha formed different conclusions?

D. The students used different ranges for their y axes.