Data Analysis and Measurement in Scientific Experiments

These flashcards cover key concepts related to data presentation, experimental design, statistical analysis, and measurement in scientific contexts.

What is the purpose of presenting collected data in figures, tables, and graphs in scientific reports?

To organize the data efficiently, allowing peers to understand methods and outcomes clearly.

What is the independent variable in an experiment?

The variable that can be controlled or changed by the experimenter.

What is the dependent variable in an experiment?

The outcome or response that is measured in the experiment after changing the independent variable.

In graphing data, what is traditionally placed on the x-axis?

The independent variable.

Explain the significance of the R-squared (R²) value in linear regression models.

It indicates how well the data fits the linear model, with values close to 1 indicating a strong correlation.

What is a well-designed graphic in a scientific context?

A graphic that efficiently describes experiments with clarity and precision, allowing for a focused discussion.

What should a figure's caption include according to scientific guidelines?

The type of graphic, its sequence number, and a description of what it represents.

When performing statistical analysis on experimental data, what is a sample?

A specific group of collected data representing a fraction of a larger population.

What are random errors in scientific measurements?

Indeterminate variations that are non-systematic and non-reproducible.

Define systematic errors in laboratory measurements.

Reproducible variations with known causes that affect measurements consistently.

What is Beer's Law in relation to absorbance of a solution?

The relationship A = εbc, where A is absorbance, ε is the molar absorptivity, b is the path length, and c is the concentration.

What must you do before loading a cuvette into a spectrophotometer?

Wipe the surface of the cuvette to remove fingerprints which can scatter light.

In which unit should temperature be measured for gas law calculations?

Kelvin.

What does it mean if data points for absorbance fall outside the range of 0.20 to 1.0 in spectrophotometry?

The sample may need to be diluted to obtain reliable data.

What type of relationship exists between pressure and volume in a gas under constant temperature?

An inversely proportional relationship; as volume increases, pressure decreases.

What is the significance of keeping a laboratory notebook?

It serves as the primary record of the laboratory work, detailing procedures, data, observations, and any modifications made.

What is molarity, and how is it expressed?

Molarity (M) is the number of moles of solute per liter of solution.

What parameter describes the reproducibility of measurement results?

Precision.

How should one handle a measurement resulting in an ambiguous number of significant figures?

Use scientific notation to clarify the exact number of significant figures.