Scientific Method (3rd Period)

1.

You are the head of the research division of the Leafy Lettuce Company. Your company is experimenting with growing lettuce using hydroponic technology. Hydroponic technology involves growing plants in containers of growth solution in a greenhouse. No soil is used. The growth solution that the company uses contains water, nitrogen, and phosphorus. The company wants to know if adding iron to this formula will improve lettuce growth. What would the INDEPENDENT VARIABLE be in the experiment?

A.

Lettuce growth
B.

Soil
C.

The growth solution
D.

Water
E.

Hydroponic technology

Correct Answer
C. The growth solution

Explanation
The independent variable in this experiment would be the addition of iron to the growth solution. This is because the company wants to test if adding iron to the formula will have an effect on lettuce growth. By adding iron to the growth solution, the company is manipulating this variable to see if it has an impact on the outcome, which is the lettuce growth.

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2.

In scientific research, the DEPENDENT VARIABLE is a factor that is measured to learn the effect of one or more independent variables.

A.

True
B.

False

Correct Answer
A. True

Explanation
The statement is true because in scientific research, the dependent variable is the factor that is being measured or observed in order to understand the impact or effect of one or more independent variables. The dependent variable is the outcome or result that researchers are interested in studying and analyzing. By manipulating the independent variables and measuring the changes in the dependent variable, researchers can gain insights into cause-and-effect relationships and draw conclusions about the relationships between variables.

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3.

In an experiment, you water three sunflower plants with salt water. Each plant receives a different concentration of salt water solution. A fourth plant receives pure water. After a two week period, the height of each plant is measured. In this experiment, the plant height is which of the following?

A.

The control
B.

The DEPENDENT variable
C.

The INDEPENDENT variable
D.

Qualitative data

Correct Answer
B. The DEPENDENT variable

Explanation
In this experiment, the height of each plant is being measured after being watered with different concentrations of salt water solution. The purpose of the experiment is to determine the effect of the salt water on the plant's growth. Therefore, the height of the plants is the dependent variable because it is the outcome or response that is being measured and is expected to be influenced by the different concentrations of salt water. The independent variable would be the different concentrations of salt water, as they are being manipulated to see how they affect the plant height. The control would be the plant that receives pure water, which is used as a baseline for comparison. Qualitative data refers to non-numerical observations or descriptions, such as the color or texture of the plants, which is not relevant to this particular question.

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4.

The following could be an example of a hypothesis: "If the outdoor temperature decreases to 32 degrees Farenheit or colder (at standard pressure), then the lake will begin to freeze because water freezes at 32 degrees Farenheit."

A.

TRUE
B.

FALSE

Correct Answer
A. TRUE

Explanation
The given statement is an example of a hypothesis because it presents a proposed explanation or prediction based on a specific condition. It follows the format of an "if-then" statement, where the condition is if the outdoor temperature decreases to 32 degrees Fahrenheit or colder, and the predicted outcome is that the lake will begin to freeze because water freezes at 32 degrees Fahrenheit. This hypothesis can be tested and proven true or false through observation and experimentation.

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5.

There will be a statistically significant difference in graduation rates of at-risk high-school seniors who participate in an intensive study program as opposed to at-risk high-school seniors who do not participate in the intensive study program." (LaFountain & Bartos, 2002, p. 57) What is the DEPENDENT variable?

A.

Graduation rates
B.

At-risk-high-school seniors
C.

Participation in the intensive study program
D.

At-risk-high-school juniors

Correct Answer
A. Graduation rates

Explanation
The dependent variable in this study is the graduation rates. The study aims to compare the graduation rates of at-risk high-school seniors who participate in an intensive study program with those who do not participate in the program. The graduation rates are the outcome or result that is being measured and compared between the two groups.

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6.

There will be a statistically significant difference in graduation rates of at-risk high-school seniors who participate in an intensive study program as opposed to at-risk high-school seniors who do not participate in the intensive study program." (LaFountain & Bartos, 2002, p. 57) What is the INDEPENDENT variable?

A.

Graduation rates
B.

At-risk-high-school seniors
C.

Participation in the intensive study program
D.

At-risk-high-school juniors

Correct Answer
C. Participation in the intensive study program

Explanation
The independent variable in this scenario is "participation in the intensive study program." This is because it is the factor that is being manipulated or controlled by the researchers to see its effect on the dependent variable, which is the "graduation rates" of at-risk high-school seniors. The researchers are comparing the graduation rates of two groups - one that participates in the program and one that does not - to determine if there is a significant difference.

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7.

"A director of residential living on a large university campus is concerned about the large turnover rate in resident assistants. In recent years many resident assistants have left their positions before completing even 1 year in their assignments. The director wants to identify the factors that predict commitment as a resident assistant (defined as continuing in the position a minimum of 2 years). The director decides to assess knowledge of the position, attitude toward residential policies, and ability to handle conflicts as predictors for commitment to the position." (LaFountain & Bartos, 2002, p. 8). What is the INDEPENDENT VARIABLE?

A.

Continuing in the position of resident assistant for at least 2 years
B.

Knowledge of the position, attitude toward residential policies, and the ability to handle conflicts
C.

The large turnover rate
D.

The director of residential living

Correct Answer
B. Knowledge of the position, attitude toward residential policies, and the ability to handle conflicts

Explanation
The independent variable in this scenario is "knowledge of the position, attitude toward residential policies, and the ability to handle conflicts." This is because the director wants to assess these factors to determine if they predict commitment as a resident assistant. The independent variable is the factor that is being manipulated or assessed in order to determine its effect on the dependent variable, which in this case is commitment to the position.

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8.

According to the graph, the value of Sarah's car INCREASED between 2001 and 2007.

A.

True
B.

False

Correct Answer
B. False

Explanation
According to the graph, the value of Sarah's car did not increase between 2001 and 2007.

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9.

Tyrosine concentration ([Tyrsonine] mM) is shown as the DEPENDENT VARIABLE in this graph.

A.

True
B.

False

Correct Answer
B. False

Explanation
The explanation for the given correct answer is that in the graph, there is no indication that the tyrosine concentration is dependent on any other variable. Therefore, it cannot be considered as the dependent variable.

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10.

The diagram below represents the change in a sprouting onion bulb when sunlight is present and when sunlight is no longer available. A student researcher hypothesized, "if the leaves of an onion bulb are removed from light for an extended period of time, then the leaves will wilt, or wither, because the leaves require sunlight to remain healthy." The above diagram, which models the results of his experiment, SUPPORTS this hypothesis.

A.

True
B.

False

Correct Answer
A. True

Explanation
The diagram represents the change in a sprouting onion bulb when sunlight is present and when sunlight is no longer available. The diagram shows that when sunlight is present, the onion bulb is healthy and sprouting. However, when sunlight is no longer available, the leaves of the onion bulb wilt and wither. This supports the student researcher's hypothesis that the leaves of an onion bulb require sunlight to remain healthy. Therefore, the correct answer is true.

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