Observations (such as measurements, genders, survey responses) that have been collected
Statistics
A collection of methods for planning experiments, obtaining data and then organizing, summarizing, presenting, analyzing, interpreting, and drawing conclusions based on the data
Population
The complete collection of all elements (scores, people, measurements, and so on) to be studied
Population
it includes all subjects to be studied
Census
The collection of data from every member of the population
Sample
A subcollection of members selected from a population
Sample data
must be collected in an appropriate way, such as through a process of random selection
If sample data are not collected in a appropriate way,
the data may be so completely useless that no amount of statistical torturing can salvage them
TYPES OF DATA???
Parameter,Statistic ,
Parameter
A numerical measurement describing some characteristic of a population.
Parameter
all of those votes to be the population considered, When Lincoln was first elected, he received 39.82% of the 1,865,908 votes cast which is 29.825.
Statistic
A numerical measurement describing some characteristic of a sample
Based on a sample
of 877 surveyed executives, it was found that 45% of them would not hire someone with a typographical error on their job application
Quantitative data
Data consists of numbers representing counts or measurement
Quantitative data
weights of supermodels
Interval level of measurement
Temperature, Years
Interval level of measurement
Data that can be arranged in order and for which differences between data values are meaningful
Interval level
shoe sizes [US vs Europe] and temperature
Interval data
can be either discreet or continuous
Ratio level of measurement
Data that can be arranged in order, for which differences between data values are meaningful, and there is an inherent zero starting point.
Ratio level of measurement
differences and ratios are meaningful
Ratio level of measurement
prices of textbooks; $50 is half of $100
Ratio level of measurement
Height of students
Ratio data
is continuous.
Ratio level of measurement
HIGHEST LEVEL OF DATA
Ratio level of measurement
can be either discreet or continuous.
Quantitative (interval and ratio) data
can be further distinguished between discrete and continuous.
Discrete Data
Data that results when the number of possible values is either a finite number or a “countable” numbers.
Discrete Data
Counting-type things
Discrete Data
number of eggs that hens lay
Continuous (numerical) Data
thickness of paper; measurement of weight
Continuous (numerical) Data
Results from infinitely many possible values that correspond to some continuous scale that covers a range of values without gaps, interruptions, or jumps.
Continuous (numerical) Data
amounts of milk from cows
Qualitative (or categorical or attribute) data
Can be separated into different categories that are distinguished by some nonnumerical characteristics.
Continuous (numerical) Data
The genders (male/female) of professional athletes
Nominal Level of Measurement
Characterized by data that consists of names, labels, or categories only
Nominal Level of Measurement
Lowest form of data. Has groups, but no ordering to the groups
Nominal Level of Measurement
cannot be arranged in an ordering scheme (such as low to high)
Nominal Level of Measurement
Survey responses of yes, no, and undecided
Nominal Level of Measurement
Colors of cars driven by college students (red, black, blue, etc.
Ordinal Level of Measurement
(Categories & groups, but with some natural order to the groups.)
Ordinal Level of Measurement
Course grades – Grades of A, B, C, D, or F
Ordinal Level of Measurement
Ranking cities; those ranked 1st, 2nd, 3rd, etcBut, the differences between ranks are meaningless
Occurs in an experiment when the experimenter is not able to distinguish between the effects of different factors.
Blinding
Subject doesn't know if he or she is receiving a treatment or placebo
Double-blind
Neither the subject nor the experimenter knows whether treatment or placebo is being administered
Blocks
Groups of subjects with similar characteristics
Completely Randomized Experimental Design
Subjects are put into blocks through a process of random selection
Rigorously Controlled Design
Subjects are very carefully chosen so that those in each block are similar in the ways that are important to the experiment.
Random Sample
Selection so that each has an equal chance of being selected
Simple Random Sample
of size n
Systematic Sampling
Select some starting point and then select every Kth element in the population
systematic sampling
7th person of a group of 10; i.e., 7, 17, 27, 37, etc., OR every 7th person i.e., 7, 14, 21, 28, etc
Convenience Sampling
Use results that are easy to get, choosing the first 10 people who get off work
Stratified Sampling
Subdivide the population into at least two different subgroups that share the same characteristics, then draw a sample from each subgroup (or stratum
Cluster Sampling
Divide the population into sections (or clusters); randomly select some of those clusters; choose all members from selected clusters
Sampling Error
The difference between a sample result and the true population result; such an error results from chance sample fluctuations
Nonsampling Error
Sample data that are incorrectly collected, recorded, or analyzed (such as by selecting a biased sample, using a defective instrument, or copying the data incorrectly
Buen Viaje lv.2 ch 8
