Variables & Experimental Design
Identify the independent variable in an investigation measuring the effect of temperature on oxygen solubility.
Temperature
Which variable goes in the first column of a data table?
Independent variable
What type of graph is used for continuous data?
Line graph
Define “anomaly.”
A result that does not fit the pattern of the data
Define “describe.”
State what is seen
State one controlled variable in the investigation measuring the effect of temperature on oxygen solubility.
Salinity / volume of water / pressure
Why should units NOT be written inside the body of a table?
Units belong in headings to avoid repetition and confusion
Which axis should the independent variable be plotted on?
X-axis
What should you do with an anomalous result?
: Repeat measurement / justify removal
Define “explain.”
Give reasons why
Explain why controlled variables are important in marine investigations. (2 parts)
A student records 23.456, 12.3, and 8.1. Correct this data to proper precision.(3 sig figs)
23.5, 12.3, 8.1 (same decimal places)
State TWO features of a good scientific graph.
State the trend ( correlation): Salinity increases → density increases.
Positive correlation
Define “analyze.”
Identify patterns/trends AND support with data
Design a method to investigate the effect of salinity on density of seawater (include 3 steps).
List TWO features of a good AICE data table.
Explain why a best-fit line is used instead of joining dots. (2 pts)
Explain why repeating trials improves reliability. (2 pts)
Give one source of systematic error in marine experiments.
Faulty equipment / calibration error
Evaluate one limitation of this experimental design and suggest an improvement. (2 pts)
Explain why calculating a mean is important in marine investigations. (2 pts)
A graph shows oxygen decreases as temperature increases. Analyze this relationship. (3 pts)
Analyze a dataset where results vary widely between trials. (3 pts)
Evaluate the reliability AND validity of an investigation measuring coral growth.