Scientific Method (1st 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 will have an effect on lettuce growth. By manipulating the presence or absence of iron in the growth solution, the company can determine its impact on the lettuce's growth.

Explanation
The dependent variable is a factor that is measured in scientific research to understand the impact of one or more independent variables. It is the variable that researchers are interested in studying and analyzing to determine how it is influenced by the independent variables. By measuring the dependent variable, researchers can gain insights into the relationship between the independent variables and the effect they have on the outcome being studied.

Explanation
In this experiment, the height of each plant is being measured. The height of the plants is dependent on the concentration of salt water solution that they receive. Therefore, the height of the plants is the dependent variable, as it is the variable that is being measured and is expected to change in response to the different concentrations of salt water. The independent variable in this experiment is the concentration of salt water solution, as it is being manipulated by the experimenter to see its effect on the dependent variable. Qualitative data refers to descriptive observations and is not applicable in this scenario.

Explanation
The given statement is an example of a hypothesis because it presents a proposed explanation or prediction based on observations and reasoning. It follows the format of an "if-then" statement, stating that if the outdoor temperature reaches 32 degrees Fahrenheit or colder, then the lake will begin to freeze because water freezes at that temperature. This statement can be tested and potentially proven or disproven through experimentation or further observation. Therefore, the answer is true.

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 or response variable that will be measured and compared between the two groups.

Explanation
The independent variable in this study is the participation in the intensive study program. This variable is being manipulated by the researchers to determine its effect on the graduation rates of at-risk high-school seniors.

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 as potential predictors of commitment to the position of resident assistant for at least 2 years. The director wants to determine 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 a longer period of time.

Explanation
According to the graph, the value of Sarah's car did not increase between 2001 and 2007. It either remained the same or decreased during that time period.

Explanation
The correct answer is False because the graph does not provide any information about the concentration of Tyrosine. The dependent variable is not shown in the graph.

Explanation
The diagram shows that when sunlight is present, the sprouting onion bulb is healthy and growing. 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 require sunlight to remain healthy. Therefore, the correct answer is true.