Smu I Sem Stat Assignments Set 2

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(Book ID: B1129)
Assignment Set- 1 (60 Marks)

Note: Each question carries 10 Marks. Answer all the questions

1. What do you mean by Statistical Survey? Differentiate between “Questionnaire” and “Schedule”.

ANS: Definition of statistical survey:
A Statistical survey is a scientific process of collection and analysis of numerical data. Statistical surveys are used to collect numerical information about units in a population. Surveys involve asking questions to individuals. Surveys of human populations are common in government, health, social science and marketing sectors.

Stages of Statistical Survey: Statistical surveys are categorized into two stages – planning and execution. The two broad stages of Statistical survey AS FOLLOWS:

Planning a Statistical Survey: The relevance and accuracy of data obtained in a survey depends upon the care exercised in planning. A properly planned investigation can lead to best results with least cost and time. Steps involved in the planning stage are as follows:

Step 1: Nature of the problem to be investigated should be clearly defined in an unambiguous manner. Step 2: Objectives of the investigation should be stated at the outset. Objectives could be to: • Obtain certain estimates

• Establish a theory
• Verify an existing statement
• Find relationship between characteristics Step 3: The scope of the investigation has to be made clear. The scope of investigation refers to the area to be covered, identification of units to be studied, nature of characteristics to be observed, accuracy of measurements, analytical methods, time, cost and other resources required. Step 4: Whether to use data collected from primary or secondary source should be determined in advance. Step 5: the organization of investigation is the final step in the process. It encompasses the determination of the number of investigators required, their training, supervision work needed, funds required.

Execution of Statistical survey: Control methods should be adopted at every stage of carrying out the investigation to check the accuracy, coverage, methods of measurements, analysis and interpretation. The collected data should be edited, classified, tabulated and presented in diagrams and graphs. The data should be carefully and systematically analysed and interpreted.

Differentiate between “Questionnaire” and “Schedule”:

Questionnaires contain simple questions and are filled by respondents. Schedules also contain questions but responses are recorded directly by the investigator.

2. The table shows the data of Expenditure of a family on food, clothing, education, rent and other items. Depict the data shown in the table using Pie chart.

|Items |Expenditure |
|Food |4300 |
|Clothing |1200 |
|Education |700 |
|Rent |2000 |
|Others |600 |

Fig: Pie-chart showing expenditure of a family on various items

3. Average weight of 100 screws in box A is 10.4 gms. It is mixed with 150 screws of box B. Average weight of mixed screws is 10.9 gms. Find the average weight of screws of box B.

• n1=100,
• n2 = 150,
• X1 = 10.4 Gms,
• [pic]= 10.9 Gms,
• X2 =?


10.9 = (100*10.4) + (150 X2) / 100+150 10.9 = 1040 + 150 X2 / 250
10.9*250 = 1040 + 150 X2
2725 = 1040 + 150 X2
150 = 2725-1040
X2 =1685 / 150
X2 = 11.23 Gms
Therefore, the average weight...
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