TYPES OF VARIOUS SAMPLING IN STATISTICS.pptx

Sampling in statistics

1. SAMPLING

2. DEFINITION OF SAMPLING The population is the entire group that you want to draw conclusions about. The sample is the specific group of individuals that you will collect data from. - we want to use the sample to represent & estimate the entire population.

3. WHY SAMPLING IS IMPORTANT? The sampling costs are cheaper and more practical than reaching every member of a target population. It saves money and time. Researchers have a higher degree of control with less complexity. A sample can be more accurate as it eliminates exposure to non-sampling errors like  non-response bias . occurs when survey participants are unwilling or unable to respond to a survey question or an entire survey It is applied when there is difficulty in having censuses .

4. PROBABILITY SAMPLING A sampling technique where a researcher selects a few criteria and chooses members of a population randomly . All the members have an equal opportunity to participate in the sample with this selection parameter.

5. Assessment of Noise Exposure and its Impact on Occupational Safety in a Manufacturing Facility Objective: Evaluate the noise exposure levels among workers in a manufacturing facility and assess the potential impact on occupational safety, health, and the environment. Criteria selected: Workers who work at least 5 years and above Simple Random Sampling: Create a list of all workers in the manufacturing facility that have been work at least 5 years. Use a random sampling method (e.g., random number generator) to select a subset of workers from the entire workforce. Stratified Random Sampling: Stratify the workforce based on job roles (e.g., machine operators, maintenance staff, supervisors). Identify workers with 5 years of working within each stratum. Randomly select samples from each stratum, ensuring proportional representation of workers.

6. Assessment of Noise Exposure and its Impact on Occupational Safety in a Manufacturing Facility Objective: Evaluate the noise exposure levels among workers in a manufacturing facility and assess the potential impact on occupational safety, health, and the environment. Criteria selected: Workers who work at least 5 years and above Systematic Sampling: Create a list or database of all eligible workers who meet the criterion of having at least 5 years of experience. Determine the sampling interval Begin at the randomly selected starting point and select every kth worker, where k is the sampling interval. (e.g. every 5 th workers) Continue the systematic sampling process until you reach the desired sample size. Cluster Sampling: Divide the workforce into clusters based on a natural grouping or division within the facility. For example, clusters could be departments, work units, or specific areas. Randomly select a predetermined number of clusters from your list. Ensure that each cluster is representative of the overall population in terms of the criterion you have set

7. NON-PROBABILITY SAMPLING A sampling technique in which the researcher selects samples based on the subjective judgment of the researcher rather than random selection.

8. Assessment of Noise Exposure among P-Hailing Riders in Pahang and Their Perception Objective: Evaluate the noise exposure levels among p-hailing riders in Pahang and their perception as p-hailing riders. Criteria selected: Riders who work fulltime and minimum of 2 years. Convenience Sampling Visit various locations in Pahang where p-hailing activities are prevalent. Approach riders present at these locations. Request their participation in the study, explaining the focus on noise exposure among p-hailing riders. Collect data from willing participants. Purposive Sampling Identify key p-hailing hubs or areas where experienced full-time riders are likely to be found. Approach selected individuals who meet your criteria. Explain the study's purpose and request their participation. Collect data from those who agree to participate.

9. Mixed-method

10. Assessment of Noise Exposure among P-Hailing Riders in Pahang and Their Perception Objective: Evaluate the noise exposure levels among p-hailing riders in Pahang and their perception as p-hailing riders. Criteria selected: Riders who work fulltime and minimum of 2 years. Quota Sampling Define quotas based on key characteristics (e.g., full-time riders with at least 2 years of experience). Approach and recruit participants until each quota is met. Collect data from riders who meet the specified criteria. Snowball Sampling Begin by recruiting a few p-hailing riders who meet your criteria. Ask these initial participants to refer other eligible riders they know. Continue this process until you reach your desired sample size. Collect data from referred participants.

11. KEY DIFFERENCES Probability Sampling Methods Non-Probability Sampling Methods Definition Samples from a larger population are chosen using a method based on the theory of probability. Researcher selects samples based on the researcher’s subjective judgment Alternatively Known as Random sampling method. Non-random sampling method Population selection Selected randomly. Selected arbitrarily. Nature The research is conclusive. (Quantitative study) The research is exploratory and pilot. (Mostly qualitative, but also for quantitative study) Sample Since there is a method for deciding the sample, the population demographics are conclusively represented. Since the sampling method is arbitrary, the population demographics representation is almost always skewed. Time Taken Takes longer to conduct - The research design defines the selection parameters before the market research study begins. Quick - Neither the sample, nor the selection criteria of the sample are undefined. Results This type of sampling is entirely unbiased; hence, the results are also conclusive. This type of sampling is entirely biased, and hence the results are biased, too, rendering the research speculative. Hypothesis There is an underlying hypothesis before the study begins, and this method aims to prove the hypothesis. The hypothesis is derived after conducting the research study.

12. SENTENCES WRITING (Probability Sampling) Title: "Assessment of Noise Exposure and its Impact on Occupational Safety in a Manufacturing Facility" Methodology Section: A probability sampling approach was adopted, utilizing a stratified random sampling design. The target population comprised all employees within the manufacturing facility, and the sampling frame was obtained from the human resources department's employee roster. Stratification was based on job roles to ensure representation across various occupational categories. Inclusion criteria stipulated a minimum of 5 years of employment and active engagement in tasks involving potential noise exposureEmployees were recruited during working hours, and informed consent was obtained before data collection.

13. SENTENCES WRITING (Non-Probability Sampling) Title: "Assessment of Noise Exposure among P-Hailing Riders in Pahang and Their Perception" Methodology Section: Participants were selected using a convenience sampling approach. P-hailing riders were approached at various locations within Pahang state, including popular pick-up and drop-off points and rest areas. This method facilitated quick access to a diverse range of participants. Following the initial convenience sampling, purposive sampling was employed to focus on p-hailing riders who met specific criteria. Criteria included full-time employment as p-hailing riders and a minimum of 2 years of experience. This intentional selection aimed to provide in-depth insights into the experiences of a subgroup with relevant characteristics.

14. SIMPLE RANDOM SAMPLING Title of Research Effects of Ambient Noise on Patient Recovery in Hospital Wards Objective To investigate the impact of ambient noise levels on the recovery outcomes of patients in hospital wards. Population All patients been admitted to hospital wards within a large medical center. Sampling Frame A comprehensive list of all patients currently admitted to various wards - obtained from the hospital records. Selection Process A random number generator is used to select a simple random sample of 150 patients from the entire list. Each patient in the list has an equal chance of being selected. Data Collection Noise levels are measured using sound level meters in the hospital wards where the selected patients are admitted. Patient recovery outcomes are assessed through a combination of medical records, post-discharge surveys, and recovery metrics. Types of Research Quantitative Types of Statistics Descriptive Statistics and Inferential Statistics Type of Potential Tests Descriptive statistics for noise levels Correlation analysis to examine the relationship between ambient noise levels and continuous variables related to patient recovery. Regression analysis to explore the impact of ambient noise levels on patient recovery outcomes while controlling for potential confounding factors. ANOVA to assess if there are significant differences in patient recovery outcomes across different levels of ambient noise. *The specific choice of tests will depend on the distribution of your data, the nature of your variables, and the research questions you aim to answer.

15. SYSTEMATIC SAMPLING Title of Research Assessment of Noise Exposure and its Impact on Occupational Safety in a Manufacturing Facility Objective To evaluate noise exposure levels among workers in a manufacturing facility and assess the potential impact on occupational safety, health, and the environment. Population The population consists of all employees working in different sections of a manufacturing facility where noise exposure is a potential concern. Sampling Frame A comprehensive list of all employees, their work areas, and the corresponding noise exposure levels - obtained from the facility's occupational health and safety records. Selection Process Determine the total number of employees (N) in the manufacturing facility, e.g., 500 employees. Set the sampling interval (k) by dividing the total number of employees by the desired sample size, e.g., k = 500 / 50 = 10. Randomly select a starting point (e.g., the 7th employee) and then select every 10th employee thereafter until the desired sample size (e.g., 50 employees) is reached. Data Collection Measure and record noise exposure levels in the work areas of the selected employees. Collect data on occupational safety incidents, health assessments, and environmental impact related to noise exposure. Types of Research Quantitative Types of Statistics Descriptive Statistics and Inferential Statistics Type of Potential Tests Descriptive statistics for noise exposure levels Correlation analysis to assess the strength and direction of the linear relationship between continuous variables, such as noise exposure levels and the frequency of safety incidents. T-Test to compare the mean noise exposure levels between groups with and without safety incidents. *The specific choice of tests will depend on the distribution of your data, the nature of your variables, and the research questions you aim to answer.

16. CLUSTER SAMPLING Title of Research Assessing Workplace Noise Levels Objective To evaluate and characterize workplace noise levels in a manufacturing facility, with a specific focus on production areas. Population All employees working in a large manufacturing facility. Sampling Frame A comprehensive list of all patients currently admitted to various wards - obtained from the hospital records. Selection Process Identify distinct production areas within the manufacturing facility (e.g., assembly line, machining area, packaging section). Randomly select a subset of production areas (clusters) from the list of all available production areas in the facility. For each selected production area, include all employees working in that area in the study. Data Collection Deploy noise measurement devices in the selected production areas to record ambient noise levels during regular working hours. Collect additional information on the specific processes, machinery, and work practices in each production area. Types of Research Quantitative Types of Statistics Descriptive Statistics and Inferential Statistics Type of Potential Tests Descriptive statistics for noise levels in each selected production area. Spatial analysis - GIS mapping to visualize the spatial distribution of noise levels across different clusters. ANOVA to compare mean noise levels between different production areas (clusters) *The specific choice of tests will depend on the distribution of your data, the nature of your variables, and the research questions you aim to answer.

17. STRATIFIED RANDOM SAMPLING Title of Research Stratified Assessment of Occupational Noise Exposure in Manufacturing Workers Objective To assess the variation in occupational noise exposure levels across different departments in a manufacturing facility. To identify specific areas of concern for targeted noise reduction interventions. Population All manufacturing workers in a large-scale production plant. Sampling Frame Comprehensive list of manufacturing workers categorized by departments (e.g., production, maintenance, administration). Selection Process Stratified random sampling is employed, where each department is treated as a separate stratum. A proportional number of participants are randomly selected from each department, ensuring representation from all areas of the manufacturing plant. Data Collection Sound level meters to measure the noise levels. Surveys are administered to gather information on workers' perceptions of noise, its impact on their well-being, and existing safety measures. Types of Research Quantitative Types of Statistics Descriptive Statistics and Inferential Statistics Type of Potential Tests Descriptive statistics to calculate mean noise levels for each department. Correlation analysis to explore the relationship between perceived noise impact and measured noise levels. ANOVA to assess if there are significant differences in mean noise levels between departments. *The specific choice of tests will depend on the distribution of your data, the nature of your variables, and the research questions you aim to answer.

18. CONVENIENCE SAMPLING Title of Research Perceptions of Workplace Noise and Its Impact on Employee Well-being Objective To explore employees' perceptions of workplace noise To understand the potential impact of noise on employee well-being. Population All employees working in a manufacturing plant. Sampling Frame List of employees in different departments of the manufacturing plant. Selection Process Employees will be recruited based on their availability and willingness to participate. Different departments will be represented, but the sample is not systematically chosen. Data Collection Surveys and Interviews: Participants will complete surveys assessing their perceptions of workplace noise, its effects on their well-being, and any suggested improvements. Observations: Researchers will conduct observations in various work areas to supplement self-reported data. Types of Research Qualitative and Quantitative Types of Statistics Descriptive Statistics and Inferential Statistics Type of Potential Tests Descriptive statistics Calculate the percentage of employees reporting high levels of stress due to noise Content analysis to analyze qualitative responses to identify recurring themes related to the impact of noise on concentration and productivity.. Chi-square test to assess if there are significant associations between the department in which employees work and their reported level of discomfort with workplace noise. *The specific choice of tests will depend on the distribution of your data, the nature of your variables, and the research questions you aim to answer.

19. PURPOSIVE/JUDGEMENT SAMPLING Title of Research Examining the Impact of Noise Exposure on Occupational Health in Manufacturing Workers Objective To investigate the specific occupational health effects of noise exposure in manufacturing workers. To identify strategies for mitigating the health impact of workplace noise. Population Manufacturing workers in a specific department of a production plant. Sampling Frame List of manufacturing workers in the target department. Selection Process Participants will be selected purposefully based on their exposure levels to workplace noise. Both high and low exposure groups will be included to capture a range of experiences. Data Collection Audiometric Testing: Measure participants' hearing thresholds to assess the impact of noise exposure on hearing. Health Surveys: Administer health surveys to gather information on reported symptoms related to noise exposure, such as stress, headaches, and sleep disturbances. In-depth Interviews: Conduct interviews with workers to explore their subjective experiences and coping mechanisms regarding workplace noise. Types of Research Qualitative and Quantitative Types of Statistics Descriptive Statistics and Inferential Statistics Type of Potential Tests Descriptive statistics to calculate the mean hearing thresholds for different frequency ranges in the high and low exposure groups. Independent samples t-test to determine if there is a significant difference in hearing thresholds between workers with high and low noise exposure. *The specific choice of tests will depend on the distribution of your data, the nature of your variables, and the research questions you aim to answer.

20. SNOWBALL SAMPLING Title of Research Exploring Workplace Noise and Safety Practices: A Snowball Sampling Approach Objective To explore the perceptions of workplace noise and safety practices among employees. To identify key individuals with diverse experiences and insights in the organization. Population Employees across various departments in a manufacturing company. Sampling Frame No predetermined list; initial participants identified based on their willingness and ability to provide insights. Selection Process Initial participants will be identified based on their accessibility and willingness to participate in the study. Participants will then refer the researcher to other individuals with relevant insights, forming a chain of referrals. Data Collection Semi-Structured Interviews: Conduct in-depth interviews with participants to gather qualitative insights on their experiences with workplace noise and safety practices. Document Review: Review safety records and incident reports to complement participant narratives. Types of Research Qualitative Types of Statistics Descriptive Statistics and Inferential Statistics Type of Potential Tests Thematic Analysis to identify themes such as the perceived effectiveness of safety measures, challenges faced by employees, and recommendations for improvement. Content Analysis to summarize incident reports to identify the types and frequencies of safety incidents related to workplace noise. *The specific choice of tests will depend on the distribution of your data, the nature of your variables, and the research questions you aim to answer.

21. QUOTA SAMPLING Title of Research Assessment of Workplace Stress and Noise Exposure in Call Center Employees Objective To examine the levels of workplace stress among call center employees. To assess noise exposure and its potential impact on stress levels. To establish a quota-based sample that reflects the demographic composition of the call center workforce. Population Call center employees in a large customer service organization. Sampling Frame List of call center employees categorized by demographic variables such as age, gender, and job roles. Selection Process Quota sampling is employed to ensure proportional representation of key demographic groups. Quotas are set for age groups, gender, and job roles based on the overall demographic distribution in the call center. Participants are then selected to fill these predefined quotas. Data Collection Surveys to measure workplace stress levels and gather information on perceived noise exposure. Quota-based sampling allows for targeted insights into stress and noise experiences across different demographic groups within the call center. Types of Research Qualitative Types of Statistics Descriptive Statistics and Inferential Statistics Type of Potential Tests Descriptive analysis to calculate mean stress scores for each demographic group. ANOVA to assess if there are significant differences in stress levels across demographic groups. Correlation analysis to explore the relationship between perceived noise levels and reported stress. *The specific choice of tests will depend on the distribution of your data, the nature of your variables, and the research questions you aim to answer.