Scientific Method (2nd Period)

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. The independent variable is the factor that is manipulated or changed by the researcher to see its impact on the dependent variable, which in this case is lettuce growth.

Explanation
The dependent variable in scientific research refers to the factor that is being measured or observed in order to understand the impact or influence of one or more independent variables. It is the variable that is expected to change as a result of manipulating the independent variables. Therefore, the statement that the dependent variable is a factor that is measured to learn the effect of independent variables is true.

Explanation
The height of the plants is the dependent variable in this experiment because it is the outcome that is being measured and observed. The independent variable is the concentration of salt water solution that each plant receives, as this is the factor that is being manipulated and controlled by the experimenter. Qualitative data refers to observations that are descriptive in nature, such as the color or texture of the plants, which is not mentioned in the given question. The control in this experiment would be the plant that receives pure water, which is used as a baseline for comparison to determine the effects of the salt water solution on the other plants.

Explanation
The given statement presents a hypothesis as it proposes a cause-and-effect relationship between two variables, the outdoor temperature and the freezing of the lake. It states that if the temperature decreases to 32 degrees Fahrenheit or colder, then the lake will begin to freeze because water freezes at 32 degrees Fahrenheit. This hypothesis can be tested through observation and experimentation to determine if it is true or false.

Explanation
The dependent variable in this study is the graduation rates. The study aims to determine if there is a statistically significant difference in graduation rates between at-risk high-school seniors who participate in an intensive study program and those who do not. The graduation rates are the outcome that is being measured and compared between the two groups.

Explanation
The independent variable in this study is the participation in the intensive study program. This means that the researchers are interested in examining how the graduation rates of at-risk high-school seniors are affected by their participation in the program. The independent variable is the factor that is manipulated or controlled by the researchers in order to observe its effect on the dependent variable, which in this case is the graduation rates.

Explanation
The independent variable in this scenario is knowledge of the position, attitude toward residential policies, and the ability to handle conflicts. These factors are being assessed by the director to determine their predictive value for commitment to the position of resident assistant. The director wants to see if having knowledge of the position, a positive attitude toward residential policies, and the ability to handle conflicts effectively will increase the likelihood of a resident assistant staying in their position for at least 2 years.

Explanation
According to the graph, the value of Sarah's car did not increase between 2001 and 2007. The line on the graph remains flat, indicating that the value stayed the same during that time period. Therefore, the answer is false.

Explanation
The graph does not provide any information about the concentration of tyrosine. Therefore, we cannot determine the dependent variable from the given graph.

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