Sample Investigation

A Sample Investigation is the process of learning about the population based on a sample that you draw from it. In this technique, instead of using all items in a universe, you use only a part of the universe for study. Also, you draw conclusions based on the sample for the entire universe. Let’s look at the objectives, essentials, merits, and demerits of a sample investigation.

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Objectives of a Sample Investigation

The primary objectives of collecting and analyzing a sample investigation are to reveal characteristics of a population as follows:

• Estimating the parameters of the population like means, median, mode, etc.
• Testing validity statements about the population
• Investigating the changes in population over time

In other words, the sampling process involves three main elements – selecting the sample, collecting the information, and also making inferences about the population.

Browse more Topics under Descriptive Statistics

• Definition and Characteristics of Statistics
• Stages of Statistical Enquiry
• Importance and Functions of Statistics
• Nature of Statistics – Science or Art?
• Application of Statistics
• Law of Statistics and Distrust of Statistics
• Meaning and Types of Data
• Methods of Collecting Data
• Census
• Classification of Data
• Tabulation of Data
• Frequency Distribution of Data
• Diagrammatic Presentation of Data
• Graphic Presentation of Data
• Measures of Central Tendency
• Mean Median Mode
• Measures of Dispersion
• Standard Deviation
• Variance Analysis

Essentials of a Sample Investigation

                                                                                                                                         

Some critical essentials of sampling include:

1. Representativeness – You must select the sample in a manner which represents the universe in its truest sense. Further, if you fail to do so, then you might get misleading results.
2. Adequacy – You should also select the size of the sample adequately which represents the parametric characteristics of the population.
3. Independence – When you select a sample, you must ensure that you select the items independently and also randomly.
4. Homogeneity – This is another important element of a sample investigation. Homogeneity means that there is no basic difference in the nature of the units in the sample and the universe.

Merits of a Sample Investigation

Here are some important merits of sampling:

1. Cost-efficient – In a sample investigation, the costs associated with the collection of data are less. This is because you collect data only from a fraction of the entire population. Therefore, it is cost-efficient.
2. Time-efficient – In sampling, you require less time to collect, analyze, and interpret the data since you are working only on a fraction of the population. Hence, it is time-efficient too.
3. Reliable – Usually, the data collected under a sample investigation is reliable because of the use of well-trained and experienced investigators or experts.
4. Flexible – When you collect data through sampling, you have a greater scope of flexibility.
5. Detailed Information – Since sampling is cost-efficient and also time-efficient, you can collect detailed information about the sample in your survey.

Demerits of a Sample Investigation

While sampling has many merits, there are some demerits associated with it too. Here is a quick look:

1. It is impossible to attain a 100 percent accuracy using this process. This is because the investigator draws conclusions about the characteristics of the population using the results that he obtains from the selected sample.
2. The results are prone to a sampling error or a random error.
3. Experts are required to ensure that the results of a sample investigation are satisfactory.
4. Sometimes, the sample does not represent the population correctly. This is because it depends on the attitude and mindset of the investigators.
5. If the population has a heterogeneous character, then you cannot use this method.

Solved Question

Q1. What are the essentials of a Sample Investigation?

Answer: The essentials of sampling are:

• The sample must truly represent the population
• Its size must be adequate
• You must select the sample randomly and independently
• The population must be homogeneous