1st PUC Statistics Question Bank Chapter 2 Organization of Data

Karnataka 1st PUC Statistics Question Bank Chapter 2 Organization of Data

1st PUC Statistics Organization of Data Two Marks Questions and Answers

Question 1.
What is meant by a statistical enquiry?
Solution:
A Statistical enquiry means a search for knowledge through statistical methods.

Question 2.
Mention the two stages of statistical enquiry.
Solution:
The two stages of statistical enquiry are:

1. Planning and preparation.
2. Execution of the survey.

Question 3.
Mention the points that are to be considered in planning an enquiry.
Solution:
In planning the following points are to be carefully considered.

1. Object of an enquiry
2. Scope of the enquiry
3. Units used for collection and measurement
4. Sources of data
5. Method of collection of data
6. Framing a format
7. Accuracy level
8. Type of enquiry

Question 4.
Mention the points that are to be considered in execution of the survey.
Solution:
The various steps to be considered at the execution are as follows:

1. Setting a team of administrators
2. Designing of questionnaire
3. Selection and training of enumerators
4. Field work by enumerators and supervision
5. Follow up work in the case of non response
6. Analysis of collected data
7. Preparation of final report

Question 5.
What is primary data?
Solution:
Data which are collected by the investigator for the first time, freshly obtained directly from the field is called primary data. They are original in nature.

Question 6.
Define secondary data.
Solution:
Secondary data is the data which has been already collected by someone and analyzed by enumerators. They are not original in nature. Secondary data is also called second hand data. And which are published in Journals, Mazgines, Newspapers, maintained as office records.

Question 7.
Mention the methods of collection of primary data.
Solution:
The different methods of collection of primary data are:

1. Direct personal observation.
2. Indirect oral interview.
3. Information through agencies.
4. Mailed questionnaires.
5. Schedules sent through enumerator.

Question 8.
Mention the sources of secondary data.
Solution:
The different sources of secondary data are:

1. Published sources
2. Unpublished sources.

Question 9.
Explain the Sources of secondary data.
Solution:
The sources of secondary are published and unpublished source.
Published source:-

1. Official publication of the state and central government
2. Foreign or Internation bodies like UNO, IMF etc.
3. Journals, periodicals, Newspapers, Magazines etc.

Unpublished source:-

1. Unpublished records maintained by government offices, Municipal offices, panchayat offices etc.
2. Unpublished records maintained by research scholars, research centers, etc.

Question 10.
What is a questionnaire?
Solution:
Questionnaire is a list of questions used by an enumerator who mails it to the respondents to get the required information.

Question 11.
Define sample.
Solution:
A few representative units selected at random from the population.

Question 12.
Define sample survey.
Solution:
Sampling survey implies enumeration of few representative units selected at random from the population. Ex: – Survey of market of prices of food grains at selected places

Question 13.
What is random sample?
Solution:
Random sample is the selection of units from the population such that each unit of the population has equal chance of being included the in the sample.

Question 14.
Define census enumeration.
Solution:
Census method is the method of collection^ of the data by complete enumeration of every unit of the population, eg., population census of India conducted once in every 10 years is a census method. In this, the information obtained is most accurate, reliable, but requires more labor, money and time.

Question 15.
What is a strata?
Solution:
The population is divided in to different groups of units called strata, which are homogeneous with respect to a specific character.

Question 16.
What is meant by statistical error?
Solution:
Statistical error is the difference between the estimated value and the actual value.

Question 17.
What are the causes for the occurrence of statistical error?
Solution:
The Causes of Errors are:

• Errors of origin : The error that occurs due to improper definition of statistical units, defective questionnaire and wrong method of enquiry is called the Error of origin.
• Error of inadequacy: The error that occurs due to incomplete data or insufficient data is called Error of inadequacy.
• Error of manipulation : The error that occurs at the time of analysis (clerical errors) is called Error of manipulation.

Question 18.
Distinguish between biased and unbiased errors.
Solution:

• Biased errors : The errors that occur with the notice of the investigator are called biased errors . These errors are prejudiced errors.
• Unbiased errors : The errors that occur without the notice of the investigator are called unbiased errors. These errors occur due to chance causes (which cannot be controlled)

Question 19.
Mention the methods of measurement of errors.
Solution:
There are two types of measurements of errors:

1. Absolute error
2. Relative error

Question 20.
What is meant by absolute error? (Define absolute error)
Solution:
Absolute Error is the arithmetic difference of actual value and the estimated value.
Absolute Error = Actual value – Estimated val ue
A.E = a – e

Quesiton 21.
What is meant by relative error? (Define relative error).
Solution:
Relative Error is the ratio of absolute error and the estimated value.

1st PUC Statistics Organization of Data Five Marks Questions and Answers

Question 1.
Explain the methods of collection of primary data with relative merits and demerits?
Solution:
1. Direct personal observation: In this method the investigator collects the required information by personal observation of the units, through the enumerator, from the informants. This methods is successively employed-Where the field of enquiry is confidential, small, greater accuracy and sufficient time is available.

• Merits: This method is most reliable, accurate and confidential.
• Demerits: This method is expensive, time consuming and this method becomes difficult where the enquiry field is large. In this method there is chance of personal bias in collection of data, needs trained and skilled personnel.

2. Indirect oral interview: This method is applied, where the required information from the informant is not possible to obtain by direct interview method. In this method the investigator/enumerator approaches the witnesses or third parties, who are capable to supply the necessary information about the first person/informant.

• Merits: This method is simple, convenient, free from bias and successively employed by New paper, Broadcasting, Investigating agencies.
• Demerits: In this method there is an ample scope of influencing the enquiry by the third person.

3. Information through agencies
Under this method, local agents or correspondents will be appointed. They collect the information and transmit it to the investigator. They may apply any method according to the intensity of the situation. Agents who collect information from the informants are generally called correspondents.

This method is generally adopted in those cases where the information is to be obtained at regular intervals from a wide area. News papers are the-examples of collection of information through agencies.

Merits :

• This method is very cheap and economical.
• It is useful where information is needed regularly.

Demerits:

• The information may be biased.
• It is difficult to maintain the degree of accuracy and uniformity.

4. Mailed questionnaire
Questionnaire is a list of questions where the answers are filled by the informants and these answers are the required information for the investigation.
The questionnaire is sent to the respondents, who are expected to write the answers in the space provided in the questionnaire.

The questionnaire will b§ sent to the informants through mail. A covering letter is also sent along with the questionnaire, requesting the informants to extend their full cooperation by giving the correct information and return the duly filled questionnaire with in a fixed time. This method is appropriate in cases where informants are spread over a wide area and are literates.

Merits:

• This method is most economical.
• It saves manpower.
• It can be widely used, where the area of investigation is large.

Demerits:

• This method cannot be used if the informants are illiterates.
• In this method many informants will not respond.
• In the case of non response, follow up work is essential.

5. Schedules sent through enumerators:
It is a widely used method of collection of primary data. A number of enumerators are selected and trained for this purpose.

Here, the trained investigator collects data through enumerators. The enumerators contact the informants and collect the information which is called schedule method. Schedule is a list of questions where the facts will be supplied by informants and recorded by enumerator.

Merits

• This method is very useful where the informants are illiterates.
• In this method the rate of non response is less.

Demerits

• In this method the training of enumerators is essential.
• This method is time consuming.
• Personal bias of the enumerators may lead to failure of enquiry.

Question 2.
What are the guidelines for the construction of a questionnaire?
Solution:
The following points are considered while framing a schedule/questionnaire.

1. Questions should be simple and easy to understand to get spontaneous answers.
2. Questions should not confuse the reader and they should give one and only one meaning.
3. The number of questions should be kept minimum.
4. If possible the questions should be capable of getting a definite answers, with either yes or no, a number, a place or a date etc.,
5. Questions should be capable of tabulating.
6. The questions should be such that the least intelligent and a educated can answer them with least trouble
7. The questions should be arranged in logical order.
8. The questions which hurt the feelings of the informant and which are of personal and confidential nature should be avoided.
9. A far as possible the questions put should be corroborator at least on the point of importance.
10. The questions should pre-tested in a small group of individuals before it is used.
11. Questionnaire should look attractive.
12. If possible a covering letter is attached along with the questionnaire.

Question 3.
Mention the merits and demerits of census enumeration.
Solution:
The merits and demerits of census enumeration are:
The merits are:-

• The results are more accurate and reliable.
• The data are collected from each and every unit of the population.
• It provides the detailed study of all the units of the population.
• Census method is free from sampling errors.

The Demerits are:-

• Non sampling errors are likely to be more in census enumeration.
• It requires more money, labour and time.
• It is not possible in some circumstances where the universe is vast.
• While procuring the data if the units are damaged, census enumeration is not suitable.

Question 4.
Mention the merits and demerits of sample survey.
Solution:
The Merits are:-

• This method requires less labour, less time and is economical.
• Sample survey is more scientific.
• This method is applied for those units which are destructive in nature.
• Sample survey is free from non sampling errors.

The Demerits are:-

• Sample survey requires adoption of appropriate sampling method and appropriate methods of analysis.
• If the population is too heterogeneous in nature, the use of sampling procedure is impossible
• Sampling errors are part and parcel of sample survey.

Question 5.
Distinguish between census enumeration and sample survey.
Solution:
Followig are Differences between Census enumeration and sample survey:
Census Enumeration

• Enumeration of each and every unit of the population is called census enumeration.
• Non sampling errors are likely to be more.
• This method is not scientific.
• This method is impossible if the population is infinite.
• This method requires more money, time and labour.
• In destructive cases this method cannot be used.

Sample survey

• Enumeration of a few representative units of the population is called sample survey.
• Sampling errors are more.
• This method is more scientific.
• This method is more suitable if the population is infinite.
• This method is economical.
• In destructive cases this method is only method which can be used.

Question 6.
Briefly explain the three methods of sampling.
Solution:
The following are some of the methods of sampling.

1. Simple random sampling.
2. Systematic sampling.
3. Stratified sampling.

1. Simple random sampling: In this method the samples are drawn in such a way that every unit of the population has equal chance of being included the in the sample. Random samples can be obtained by i) Lottery method ii) Use of Random numbers.

2. Stratified sampling: In this method the population is divided in to different groups of units called strata, which are homogeneous with respect to a specific character. From each stratum appropriate number of units are randomly selected. This method is called Stratified sampling.

3. Systematic sampling: In this method a population is serially arranged either in alphabetical or numerical order. Then first unit is selected at random between first and kthunit, and then every kth unit is selected. The number of units selected form the sample size.

Here  = $$\frac{\text { No. of units in the population }}{\text { No. of units in the sample }}$$

ie., One number will be selected between 1 and k by lottery method . Let it be ‘a’.
Then the sample units are : a, a+k , a+2k,…, a+ (n – 1)k.
For example, if N = 100, n = 10, then k = $$\left(\frac{N}{n}\right)=\left(\frac{100}{10}\right)$$ = 10
If a = 5 , then. the sample units will be 5, 15 , 25, ….. , 995.