Psychology Module 2, Independent Variable
placebo effect
*subjects expectations influence their behavior *experimenter effect *experimenters expectations of the study unintentionally influence the results of the study
steps in the scientific method
1. formulate question 2. develop hypothesis (prediction) 3. test hypothesis 4. draw conclusions 5. report your results
methods used
1. non-experimental method (observational) 2. correlational method (measurements) 3. experimental method (experiments)
What is the control? Students measured the temperature of the water at different depths in Lake Skywalker and found that the temperature varied.
Lake Skywalker
A florist wants to see if Product X will extend the life of cut flowers so that they last longer. What is the dependent variable?
Life of flowers
What is the control variable in the following sentence: The time it takes to run a mile depends on the person's running speed.
Mile
What is the independent variable in the following sentence: A study was done to find if different tire treads affect the braking distance of a car.
Tire treads
Control Variable
A variable that is kept constant during a controlled experiment.
You want to measure the effect of different amounts of oxygen on the rate of yeast growth. What is the independent variable?
Amount of oxygen
What is the independent variable in the following sentence: The height of bean plants depends on the amount of water they receive.
Amount of water
experiment
a controlled scientific procedure in which you manipulate variables to test a hypothesis (try to learn about cause and effects relationships)
correlation
a measure of the relationship between two variables (x&y)
Orchids were studied to determine if the amount of humidity affected the flowering of these plants. Which of these was the independent variable in this study?
amount of Humidity
variable
anything that can change or vary. (gender, scores, temperatures, age)
What is the dependent variable in the following sentence: A study was done to find if different tire treads affect the braking distance of a car.
Braking distance
What is the control variable in the following sentence: A study was done to find if different tire treads affect the braking distance of a car.
Car
surveys
ask a series of questions to a group about the topic being studied +data from large numbers from people +can study non displayed behaviors -some responses may be inaccurate or false
Quasi-Experimental Design
Compares 2 groups of people but is used when it is not feasible or ethical to use random assignment
You want to test a new drug that supposedly prevents sneezing in people allergic to grass. What is the independent variable?
Drug
What is the control variable in the following sentence: The height of bean plants depends on the amount of water they receive.
bean plants
What is the independent variable: Students measured the temperature of the water at different depths in Lake Skywalker and found that the temperature varied.
depth
population
entire group
You want to see if playing music makes plants grow taller. What is the independent variable in this experiment?
Playing music
Control Group
Group that is exposed to all experimental conditions, except the independent variable.
What is the dependent variable in the following sentence: The height of bean plants depends on the amount of water they receive.
Height of the bean plants.
You want to test a new drug that supposedly prevents sneezing in people allergic to grass. What is the dependent variable?
Sneezing
What is the dependent variable in the following sentence: The time it takes to run a mile depends on the person's running speed.
TIME
An entomologist (bug scientist) wants to determine if temperature changes how many times a cricket chirps. What is the independent variable?
Temperature
Dependent Variable
The experimental factor that is being measured; the variable that may change in response to manipulations of the independent variable
Independent Variable
The experimental factor that is manipulated; the variable whose effect is being studied.
double blind study
neither experimenter nor subjects knows if the subjects are in the experimental or control group
What is the control variable in the following sentence? The higher the temperature of the air in the oven, the faster a cake will bake.
oven/ cake
representative sample
randomly selected group from the larger population
You think that a certain part of your brain is important in memory. To test this, you will remove this part of the brain from rats and see if they remember how to get through the maze. What is the dependent variable in this experiment?
remembering how to get through the maze
You think that a certain part of your brain is important in memory. To test this, you will remove this part of the brain from rats and see if they remember how to get through the maze. What is the independent variable in this experiment?
removing a part of the brain
What is the independent variable in the following sentence: The time it takes to run a mile depends on the person's running speed.
running speed
subject
specific group or individual
correlation coefficient (r)
strength and direction of the relationship +ability to predict the value of the other variables -correlation does not prove causation
case study
study of one subject/group in great detail +a lot of detail -cannot apply results to other
naturalistic observations
study people or animals in their natural environment +realistic picture of behavior -observer effect: tendency of subject to behave differently because they know they are being observed
laboratory observation
study subject in a (laboratory) more controlled behavior +control over environment -artificial situation that may result in artificial behavior
single blind study
subjects do not know if in experimental or the control group but experimenter does
experimental group
subjects who are exposed to what is being manipulated (IV) ex. caffeine
control group
subjects who are not exposed to the IV and may receive a placebo (inactive) treatment (keep the same) ex. decaf
scientific method
system of gathering data so bias and error is reduced
What is the dependent variable? Students measured the temperature of the water at different depths in Lake Skywalker and found that the temperature varied.
temperature
What is the independent variable in the following sentence: The higher the temperature of the air in the oven, the faster a cake will bake.
temperature of the oven
observer bias
tendency of observers to see what they expect/want to see
Experimental Group
the group in an experiment that receives the variable being tested
dependent variable (DV)
the measurable effects of the changes to the IV (wait and see)
What is the dependent variable in the following sentence: The higher the temperature of the air in the oven, the faster a cake will bake.
the time it takes the cake to bake.
independent variable (IV)
the variable the researcher manipulates to observe the effects or the change (I change it)
An entomologist (bug scientist) wants to determine if temperature changes how many times a cricket chirps. What is the dependent variable?
times a cricket chirps