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A researcher notices a positive correlation between the height of a plant and nutrient concentration over time. Based on this observation, what conclusion does he reach?

A. The height of a plant increases in the absence and presence of the nutrients

B. When the amount of nutrients available to the plant decreases, its height increases.

C. The amount of nutrients available to a plant is independent of how tall the plant gets

D. When the amount of nutrients available to the plant increases, its height also increases.

Answer Explanation:

Because this is a positive correlation, if the nutrient concentration increases or decreases, plant height will either increase or decrease accordingly.

While analyzing data, scientists tend to observe cause-and-effect relationships. These relationships can be quantified using correlations. Correlations measure the amount of linear association between two variables. There are three types of correlations:

Positive correlation: 
As one variable increases, the other variable also increases. This is also known as a direct correlation.

Negative correlation: 
As one variable increases, the other decreases. The opposite is true if one variable decreases. A negative correlation is also known as an inverse correlation or an indirect correlation.

No correlation: 
There is no connection or relationship between two variables.

Therefore, the Correct Answer is D.

More Questions on TEAS 7 Science

  • Q #1: A researcher notices a positive correlation between the height of a plant and nutrient concentration over time. Based on this observation, what conclusion does he reach?

    A. The height of a plant increases in the absence and presence of the nutrients

    B. When the amount of nutrients available to the plant decreases, its height increases.

    C. The amount of nutrients available to a plant is independent of how tall the plant gets

    D. When the amount of nutrients available to the plant increases, its height also increases.

    Answer Explanation

    Because this is a positive correlation, if the nutrient concentration increases or decreases, plant height will either increase or decrease accordingly.

    While analyzing data, scientists tend to observe cause-and-effect relationships. These relationships can be quantified using correlations. Correlations measure the amount of linear association between two variables. There are three types of correlations:

    Positive correlation: 
    As one variable increases, the other variable also increases. This is also known as a direct correlation.

    Negative correlation: 
    As one variable increases, the other decreases. The opposite is true if one variable decreases. A negative correlation is also known as an inverse correlation or an indirect correlation.

    No correlation: 
    There is no connection or relationship between two variables.

  • Q #2: What standard is used to make comparisons in experiments?

    A. Sample size

    B. Control group

    C. Dependent variable

    D. Independent variable

    Answer Explanation

    A control group is a factor that does not change during an experiment. Due to this, it is used as a standard for comparison with variables that do change such as a dependent variable.

    Recall that these make up the scientific method, described below:

    • Problem: The question created because of an observation. Example: Does the size of a plastic object affect how fast it naturally degrades in a lake?
    • Research: Reliable information available about what is observed. Example: Learn how plastics are made and understand the properties of a lake.
    • Hypothesis: A predicted solution to the question or problem. Example: If the plastic material is small, then it will degrade faster than a large particle.
    • Experiment: A series of tests used to evaluate the hypothesis. Experiments consist of an independent variable that the researcher modifies and a dependent variable that changes due to the independent variable. They also include a control group used as a standard to make comparisons. 
      • Example: Collect plastic particles both onshore and offshore of the lake over time. Determine the size of the particles and describe the lake conditions during this time period.
    • Observe: Analyze data collected during an experiment to observe patterns. 
      • Example: Analyze the differences between the numbers of particles collected in terms of size.
    • Conclusion: State whether the hypothesis is rejected or accepted and summarize all results.
    • Communicate: Report findings so others can replicate and verify the results.

  • Q #3: In which state of matter do the particles of iron have the lowest amount of cohesion?

    A. Solid iron particles have the lowest amount of cohesion

    B. Liquid iron particles have the lowest amount of cohesion

    C. Gaseous iron particles have the lowest amount of cohesion

    D. The particles have the same amount of cohesion in all states of matter.

    Answer Explanation

    The particles in a sample of gas are farther apart than in solids or liquids and therefore have the lowest amount of cohesion.

    • Cohesion is the tendency of particles of the same kind to stick to each other.
    • A solid has the lowest amount of energy because its particles are packed close together. Liquids have more energy than a solid, and gases have more energy than solids or liquids because the cohesive forces are very weak.