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Data analysis includes the attribute salary
Values for salary: 30, 36, 47, 50, 52, 52, 56, 60, 63, 70, 70, 110
Mean: 58
Median: 54
Mode: 52
Midrange: 140 - 30 = 110
First Quartile (Q1): 48.5
Third Quartile (Q3): 66
Boxplot: 30, 48.5, 54, 66.5
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Data collection is gathering information about a subject
Importance of complete and ethical data collection for accurate analysis
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Primary data: collected firsthand, costly, through observations, surveys, etc.
Secondary data: already collected, affordable, from various sources, may not meet current research purpose
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Data collection methods include surveys with unbiased questions
Types of surveys: online, face-to-face
Questionnaire administration methods: mailed, collective
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Questionnaire types: closed-ended, open-ended
Forms of questions in a questionnaire
Advantages and disadvantages of questionnaires
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Data collection methods: Transactional Tracking, Interviews, Focus Groups
Transactional Tracking for targeted marketing decisions
Interviews and Focus Groups for qualitative and quantitative data
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Data collection methods: Observation, Online Tracking, Forms
Observation for real-time user interaction insights
Online Tracking for behavioral data gathering
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Observational methods involve looking and listening carefully
Types of observation: Structured, Unstructured, Participant, Non-participant
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Structured Observation: planned in advance, useful for large-scale studies
Example: patient reaction to hospital in different phases
Advantages and disadvantages of Structured Observation
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Unstructured Observation: no advance design, observer decides on the spot
Example: observing a child playing with a new toy
Strengths and weaknesses of Unstructured Observation
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Participant Observation
Observer is actively present in the observed setting.
Advantage: Allows for clarification and interaction with people.
Disadvantage: Inexperienced observer may miss relevance and influence behavior.
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Non-participant Observation
Observer remains detached and only observes.
Strength: Collects information without being influenced.
Example: Plainclothes policemen at public events.
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Sampling
Primary data collection when secondary data are unavailable.
Population Method (Census Method) vs. Sample Method.
Population classified as Finite or Infinite, Real or Hypothetical.
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Classification of Population
Finite Population: Countable elements.
Infinite Population: Uncountable elements.
Real vs. Hypothetical Population.
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Merits and Demerits of Census Method
Data from every unit of the population.
Representative and reliable data.
Intensive study possible.
Time-consuming and costly.
Not suitable for all research types.
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Sampling Population
Learning about the population through a sample.
Steps in sampling framework for making inferences.
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Sampling Frame
Certain groups of interest within the population.
Relationship between Population, Sampling Frame, and Sample.
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Methods of Sampling
Statistical data collection through various methods.
Includes Convenience, Simple Random Sampling, Cluster Sampling, etc.
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Probability Sampling Methods
Every member has a chance of selection.
Used in quantitative research to eliminate bias.
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Simple Random Sampling
Every item in the population has an equal chance of selection.
Steps for minimizing biases in the sampling process.
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Simple Random Sampling Example
Steps for obtaining a simple random sample for outcomes in trauma hospitals.
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Cluster Sampling
Dividing the population into clusters based on demographic parameters.
Random selection of clusters for effective survey results.
Systematic Sampling
Definition: Choosing sample members at regular intervals
Process: Selection of a starting point, sample size, and regular intervals
Example: Selecting every 10th individual from a population of 5000 to form a sample of 500
Stratified Random Sampling
Definition: Dividing the population into non-overlapping groups
Purpose: Representing the entire population accurately
Example: Creating strata based on annual income divisions for targeted analysis
Probability Sampling Advantages
Benefits:
Reduce sample bias
Ensure diverse population representation
Create an accurate sample for well-defined data collection
Non-Probability Sampling
Definition: Sample selection based on researcher's discretion
Usage: Preliminary research stages or cost constraints
Output may lead to skewed results in some cases
Convenience Sampling
Dependence: Ease of access to subjects
Example: Surveying customers at a mall or passers-by on a busy street
Commonly used in resource-limited situations like startups or NGOs
Judgmental or Purposive Sampling
Definition: Samples formed based on researcher's discretion
Criteria: Selection based on the purpose of the study and target audience understanding
Snowball Sampling
Usage: When subjects are difficult to trace
Example: Applied in sensitive topics like HIV/AIDS surveys
Quota Sampling
Selection: Based on pre-set standards
Purpose: Rapid method of collecting samples with specific attributes
Advantages of Non-Probability Sampling
Usage:
Create hypotheses with limited prior information
Conduct exploratory research or pilot studies
Address budget and time constraints for preliminary data collection
Differences between Probability and Non-Probability Sampling
Probability Sampling:
Randomly selected samples
Used to reduce sampling bias
Non-Probability Sampling:
Subjective judgement of researchers
Useful in specific environments with similar characteristics among