Question Bank — Understanding Data

NCERT Class 12 Computer Science · Chapter 7 · CBSE Board Pattern

Class 12 Computer Science Chapter 7 Question Bank CBSE Board Pattern

Section A — MCQs (1 mark each)

  1. Which of the following is an example of structured data?
    (a) A social media post containing text and images
    (b) A table storing ModelNo, ProductName, UnitPrice and Items_in_Inventory
    (c) An email with varying number of paragraphs and attachments
    (d) A video file consisting of frames

  2. The singular form of the word “data” as mentioned in the chapter is:
    (a) Datum
    (b) Data-item
    (c) Attribute
    (d) Variable

  3. Metadata is best described as:
    (a) Data stored in rows and columns
    (b) Data about data
    (c) Raw facts collected from sensors
    (d) Output generated after processing

  4. Which statistical measure is defined as “the value that appears most frequently in a data set”?
    (a) Mean
    (b) Median
    (c) Mode
    (d) Range

  5. An outlier in a data set is:
    (a) The middle value after sorting
    (b) An exceptionally large or small value compared to other values
    (c) The most frequent value
    (d) The difference between maximum and minimum values

Assertion-Reason Questions

  1. Assertion (A): Data must be processed and analysed before decisions can be taken.
    Reason (R): Raw data in large volumes do not reveal hidden traits or patterns directly to humans.
    (a) Both A and R are true and R is the correct explanation of A
    (b) Both A and R are true but R is not the correct explanation of A
    (c) A is true but R is false
    (d) A is false but R is true

  2. Assertion (A): Structured data can be easily stored in tabular format.
    Reason (R): Each column represents an attribute and each row represents an observation.
    (a) Both A and R are true and R is the correct explanation of A
    (b) Both A and R are true but R is not the correct explanation of A
    (c) A is true but R is false
    (d) A is false but R is true

  3. Which of the following is NOT a measure of central tendency?
    (a) Mean
    (b) Median
    (c) Mode
    (d) Range

  4. The range of the height data [85, 90, 90, 100, 102, 110, 110, 110, 115] is:
    (a) 20 cm
    (b) 30 cm
    (c) 115 cm
    (d) 85 cm

  5. Which device is listed in the chapter as a digital storage device?
    (a) Keyboard
    (b) Solid State Drive (SSD)
    (c) Monitor
    (d) Printer

Section B — Very Short Answer (2 marks each)

  1. Define the term ‘data’ as given in the chapter.
  2. Differentiate between structured data and unstructured data with one example of each.
  3. What is metadata? Give one example from the chapter.
  4. State any two limitations of file processing mentioned in the context of data storage.
  5. Calculate the mean of the following height data: [90, 102, 110, 115, 85, 90, 100, 110, 110].
  6. What is the mode of the height data [85, 90, 90, 100, 102, 110, 110, 110, 115]?

Section C — Short Answer (3 marks each)

  1. List the basic steps of the data processing cycle as shown in the chapter with a brief description of each step.
  2. Using the height data [85, 90, 90, 100, 102, 110, 110, 110, 115], find the median and justify your answer.
  3. A shop maintains the kitchen-items inventory table given in the chapter. Explain how the shop owner can obtain the total value of inventory using the data.
  4. Calculate the range of the temperature data 34, 34, 27, 28, 27, 34, 34 and state why range alone may not be sufficient when outliers are present.
  5. Distinguish between mean and median with respect to their sensitivity to outliers, citing the definition given in the chapter.

Section D — Long Answer (5 marks each)

  1. Explain the complete data processing cycle with the help of the ATM withdrawal example given in the chapter.
  2. Write the step-by-step procedure (algorithm) to compute the standard deviation of a given list of numeric values. Show a trace table for the height data [90, 102, 110, 115, 85, 90, 100, 110, 110] whose mean is 101.33.
  3. A school wants to prepare a list of students eligible for merit-cum-means scholarship. Describe the complete data collection, storage and processing steps that the school should follow.

Section E — Case/Source-Based (4 marks each)

Case 1

A grocery shop wants to analyse sales data to decide shelf placement. Sales records show that bedsheets and groceries are frequently bought together.

(a) Identify the type of data (structured/unstructured) being collected.
(b) Name two attributes that should be recorded for each sale transaction.
(c) Which statistical technique can be used to find the most frequently sold item?
(d) State one decision the shop owner may take after processing the data.

Case 2

A school is organising its annual day and needs to identify parents who are alumni of the same school for felicitation.

(a) Which mode of data collection should be used?
(b) List any three attributes required to be collected.
(c) Which statistical measure will help find how many students have both parents as alumni?
(d) How can variability in the age of parents be measured?

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Section A

  1. (b)
  2. (a)
  3. (b)
  4. (c)
  5. (b)
  6. (a)
  7. (a)
  8. (d)
  9. (b)
  10. (b)

Section B

  1. Data refer to unorganised facts/characters/numbers/symbols that can be processed to generate meaningful information.
  2. Structured data are organised in rows and columns (e.g., inventory table); unstructured data have no fixed row-column format (e.g., newspaper articles).
  3. Metadata is data about data (e.g., image size, type, resolution for an image file).
  4. Any two: difficulty in handling large volumes, data redundancy, data inconsistency, security issues.
  5. Mean = 101.33 cm (sum = 912, n = 9).
  6. Mode = 110 (highest frequency = 3).

Section C

  1. Input → Storage → Processing → Output (with brief description of each).
  2. After sorting, middle value (5th position) = 102 cm.
  3. Multiply Unit Price by Items_in_Inventory for each row and sum the products.
  4. Range = 34 – 27 = 7 °C; range uses only extreme values and is affected by outliers.
  5. Mean is affected by outliers; median is the central value after sorting and is less affected.

Section D

  1. Detailed explanation using ATM example covering all four steps of the cycle.
  2. Algorithm steps + trace table showing calculation of squared differences and final σ.
  3. Complete description of data collection from students, storage in files/DBMS, processing steps to filter eligible students.

Section E

Case 1: (a) Structured (b) Item name, quantity (c) Mode (d) Place bedsheets near groceries.
Case 2: (a) Survey/form (b) Student name, Father’s school, Mother’s school (c) Mode or counting (d) Range or standard deviation.

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All questions are answerable from the NCERT chapter text. Reviewed by GFIS faculty.