Ch. 1 Flashcards
(27 cards)
Data
observations (such as measurements, genders, survey responses. ect) that have been collected
Statistics
the science of planning studies and experiments, obtaining data and then organizing, presenting, analyzing, and drawing conclusions based on the data
Population
a population is the COMPLETE collection of all individuals (scores, people, measurements, etc.) to be studied
Census
the collection of data from EVERY member of the population
Sample
the collection of data from a SUBCOLLECTION of members selected from a population
Voluntary Response Sample (or Self-Selected Sample)
one in which the respondents themselves decide whether to be included. EX: internet polls
Statistical signigicanse
when determining statistical significance, consider the probability of something occurring by chance. If something could have occurred by chance it is NOT statistically significant
Practical Significance
statistical significance DOESN”T EQUAL practical significance
Parameter
a numerical measurement describing some characteristic of a POPULATION
Statistic
a numerical measurement describing some chracteristic of a SAMPLE
Quantitative (or Numerical) Data
data that consists of numbers representing counts or measurements EX: AGES, HEIGHT (MEAN IS IMPORTANT)
Categorical (or Qualitiative) Data
data that can be separated into different categories that are distinguished by some non-numeric characteristic EX: HAIR COLOR, GENDER, SEX (MEAN IS NOT IMPORTANT)
Discrete Data
data that results when the number of possible values is either a finite number or a “countable number” EX; # OF STUDENTS IN CLASS, # OF KEYS
Continuous data
data that results from infinitely many possible values that correspond to some continuous scale that covers a range of values without gaps, interruptions, or jumps EX; TEMPERATURE (73.1234….., LIQUID VOLUME)
Nominal Level of Measurement
CATEGORICAL
characterized by data that consists of names, labels, or categories only the data cannot be arranged in any ordering scheme (such as low to high) EX; HAIR COLOR, POLITICS
Ordinal Level of Measurement
CATEGORICAL
data that can be arranged in some ORDER but differences (obtained by subtraction) BETWEEN DATA VALUES EITHER CANNOT BE DETERMINED OR ARE MEANINGLESS EX; RANKINGS( 1ST PLACE IS NOT 2X BETTER THAT 2ND)
Interval Level of Measurement
QUANTITATIVE
similar to the ordinal level; DATA CAN BE ARRANGED IN SOME ORDER, but the diffrences ARE MEANINGFUL, however, data at this level do not have a natural zero starting point (where none of the quantity is present) EX TEMPERATURE “0” DEGREES DOES NOT MEAN NO HEAT
Ratio level of Measurement
QUANTITATIVE
similar to the interval level with the additional property that there IS A NATURAL ZERO STARTING POINT ( WHERE ZERO INDICATES THAT NONE OF THE QUANTITY IS PRESENT) for values at this level, differences and ratios are both meaningful. EX; AGE, NUMBER OF KEYS
Observational study
a study in which we observe and measure specific characteristics, but we don’t attempt to modify the subjects being studied EX; SURVEY
Experiment
a study in which we apply some treatment and then we observe its effects on the subjects EX; DRUG STUDY
Simple Random Sample
a sample of size ‘n’ subjets selected in such a way that EVERY POSSIBLE SAMPLE OF THE SAME SIZE has the SAME CHANCE OF BEING CHOSEN
Random Sample
a sample in which members from the population are selected in such a way tat each INDIVIDUAL MEMBER has an EQUAL CHANCE OF BEING SELECTED
Systematic sample
a sample in which we select some starting point and then select every ‘kth’ (such as every 10th) element in the population. EX; EVERY 5TH STUDENT
Convenience sampling
a sample that is very easy to collect EX; CLASS SURVEY ( THE VALIDITY OF THE DATA DEPENDS ON THE POPULATION I’M TRYING TO STUDY
