Independent/Dependent Variables
The variable that is intentionally changed in an experiment
Independent Variable
This graph is best for showing change over time
line graph
The dog is shivering, so he is cold. Is this an observation or an inference?
inference
It smells like cookies are baking.
Qualitative
information collected during an experiment
data
The variable that is measured in an experiment
Dependent variable
If a company needs to display percentages of different costs for a budget, what kind of graph should they use?
pie chart / circle graph
Sarah has glasses. Is this an observation or an inference? If observation, is it qualitative or quantitative?
Observation, qualitative
47% of the freshmen class owns a dog.
quantitative
False-- usually there are multiple trials conducted, or errors cause scientists to have to repeat steps.
The independent variable goes on the __-axis and the dependent variable goes on the __-axis.
Independent: x, Dependent: y
this type of graph is best for comparing categories or groups
bar graph
There is a gallon of milk on that shelf.
Quantitative
Experiment: I want to see which kind of dog food my dog will eat the most of. So, I give him a different kind of dog food each week for 4 weeks and weigh how much food he leaves in his bowl. What are at least 2 CONSTANTS I would need to have?
same type of bowl, same amount of food given, same amount of activity each day, same amount of attention given to the dog
Experiment: I want to see which kind of dog food my dog will eat the most of. So, I give him a different kind of dog food each week for 4 weeks and weigh how much food he leaves in his bowl. What is the independent variable in this experiment?
The type of food
What must every graph have so that viewers know what data is shown?
title, labels, and units
inference
I heard 3 bad notes when you were practicing just now.
quantitative
1. If currency is your variable, what are some units you could have?
2. If you have units of meters, yards, inches, or feet, what is a variable you could be measuring?
1. US dollars, euros, pesos, etc.
2. length, height, distance
Experiment: I want to see which kind of dog food my dog will eat the most of. So, I give him a different kind of dog food each week for 4 weeks and weigh how much food he leaves in his bowl. What is the Dependent variable in this experiment?
How much food the dog leaves behind/ how much he eats
A farmer plants sunflowers into Pot A and Pot B. They receive the same conditions except for different amounts of water each day. Here are the results after 3 months:
Pot Water Height Mass
Pot A 50 mL water 20 cm 4 grams
Pot B 100 mL water 45 cm 7 grams
What were the variables in this experiment and what trend do you see between them?
More water (the independent variable) caused an increase in both height and mass (the dependent variables) for the sunflower plants.
Observation or Inference: based on the five senses.
Give two examples.
Observation (examples vary)
What is the difference between quantitative and qualitative data? (Be specific)
Quantitative describes observations that include numbers.
Qualitative describes any observations or data that are non-numerical, and include any of the 5 senses.
A ______ is a factor in an experiment, a ______ tells how that factor is being measured (inches, feet, seconds, etc.)
Variable, unit