stats exam 1
Discrete variable
- Has separate, indivisible categories - No values can exist between two neighboring categories
Continuous Variable
-Have an infinite number of possible values between any two observed values - Every interval is divisible into an infinite number of equal parts
Real Limits
Real Limits are the boundaries of each interval representing scores measured on a continuous number line
A researcher conducts an experiment to determine whether moderate doses of St. Johns Wort have any effect of memory for college students. For this study, what is the independent variable?
The amount of St. Johns Wort given to each participant
ordinal
categorize observations by size/magnitude, ie. s, m, l; low, medium, high; rank in class
Which of the following is an example of a discrete variable?
gender
Independent Variable
is the variable (sometimes) manipulated by the researcher - Independent because no other variable in the study influences its value (hypothetically)
nominal
label and catergorize, nothing to do with numbers, ie. gender, art vs. non art majors
preferred central tendency on ordinal scale
median
Dependent Variable
one observed to assess the effect of treatment - "Depends" on independent variable (hypothetically)
interval
ordered categories with equal intervals in between, absent 0 point, ie. temperature, iq, golf scores
ratio
ordered categories with equal intervals in between, absolute 0 point, ie. number of correct answers, time to complete a task, gain in height since last year
The participants in a research study are classified as high, medium, or low in self-esteem. What measurement scale is being used to classify self-esteem?
ordinal
What kind of measurement scale is necessary to conclude that one score is twice a big as another?
ratio
A recent study reports that students who just finished playing a prosocial video game were more likely to help others than students who had played a neutral or antisocial game. For this study, what is the independent variable?
the kind of game given to students