Question

address the following in the area below: a. what is the independent variable in this experiment? b. what is the dependent variable in this experiment? c. why was a bar graph selected to present these data? could the authors have used a line graph? d. write a statement summarizing the results. specifically address the trends from 1972-1992, 1995-2000 and 2001-2004.

Explanation:

To solve this, we analyze each part based on experimental design and graph interpretation (Natural Science, likely Biology/Psychology/other experimental subfields):

Part A: Independent Variable

The independent variable is the factor manipulated or observed over time. From the x - axis (years: 1972, 1976, …, 2004), the independent variable is time (specifically, the year).

Part B: Dependent Variable

The dependent variable is what’s measured (y - axis, with values like 0, 10000, 20000, 30000). Assuming the y - axis represents a measured quantity (e.g., number of events, population, experimental outcomes), the dependent variable is the quantity plotted on the y - axis (e.g., “number of [outcome]” or the measured response).

Part C: Bar Graph vs. Line Graph

• A bar graph is used for discrete, categorical data (e.g., distinct years as categories, not a continuous scale). Years here are treated as separate categories (each bar = one year), so a bar graph is appropriate for comparing values across distinct time - points.
• A line graph is for continuous data (e.g., time as a continuous scale with data points connected). Since years are discrete (not a continuous interval with intermediate values), a line graph would be less appropriate (it implies a continuous trend between years, which may not exist here).

Part D: Trend Summary

• 1972–1992: Observe the bar heights (y - axis values). If bars are short (low y - values) initially and increase slightly, summarize: “From 1972 to 1992, the dependent variable (e.g., number of [outcome]) remained relatively low, with gradual increases over time.”
• 1995–2000: If bars grow taller, summarize: “From 1995 to 2000, the dependent variable showed a more rapid increase, reaching higher values.”
• 2001–2004: If bars stabilize or continue increasing, summarize: “From 2001 to 2004, the dependent variable maintained (or continued) its elevated level (or growth).”

Final Answers (Tailored to Graph Details, Assuming Y - Axis is a Measured Quantity):

A. Independent variable: Year (time)
B. Dependent variable: The quantity plotted on the y - axis (e.g., number of [experimental outcome])
C. Bar graph: Years are discrete categories (not continuous), so bars compare values across distinct time - points; a line graph implies continuous data (inappropriate here).
D. Example trend: “From 1972–1992, the measured quantity (y - axis) was low with slow growth. 1995–2000 saw rapid increases, and 2001–2004 maintained high values (or continued growing).” (Adjust based on actual bar heights.)

Answer:

To solve this, we analyze each part based on experimental design and graph interpretation (Natural Science, likely Biology/Psychology/other experimental subfields):

Part A: Independent Variable

The independent variable is the factor manipulated or observed over time. From the x - axis (years: 1972, 1976, …, 2004), the independent variable is time (specifically, the year).

Part B: Dependent Variable

The dependent variable is what’s measured (y - axis, with values like 0, 10000, 20000, 30000). Assuming the y - axis represents a measured quantity (e.g., number of events, population, experimental outcomes), the dependent variable is the quantity plotted on the y - axis (e.g., “number of [outcome]” or the measured response).

Part C: Bar Graph vs. Line Graph

• A bar graph is used for discrete, categorical data (e.g., distinct years as categories, not a continuous scale). Years here are treated as separate categories (each bar = one year), so a bar graph is appropriate for comparing values across distinct time - points.
• A line graph is for continuous data (e.g., time as a continuous scale with data points connected). Since years are discrete (not a continuous interval with intermediate values), a line graph would be less appropriate (it implies a continuous trend between years, which may not exist here).

Part D: Trend Summary

• 1972–1992: Observe the bar heights (y - axis values). If bars are short (low y - values) initially and increase slightly, summarize: “From 1972 to 1992, the dependent variable (e.g., number of [outcome]) remained relatively low, with gradual increases over time.”
• 1995–2000: If bars grow taller, summarize: “From 1995 to 2000, the dependent variable showed a more rapid increase, reaching higher values.”
• 2001–2004: If bars stabilize or continue increasing, summarize: “From 2001 to 2004, the dependent variable maintained (or continued) its elevated level (or growth).”

Final Answers (Tailored to Graph Details, Assuming Y - Axis is a Measured Quantity):

A. Independent variable: Year (time)
B. Dependent variable: The quantity plotted on the y - axis (e.g., number of [experimental outcome])
C. Bar graph: Years are discrete categories (not continuous), so bars compare values across distinct time - points; a line graph implies continuous data (inappropriate here).
D. Example trend: “From 1972–1992, the measured quantity (y - axis) was low with slow growth. 1995–2000 saw rapid increases, and 2001–2004 maintained high values (or continued growing).” (Adjust based on actual bar heights.)