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REVISION AND PRACTICE
Week 3 revision and practice
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Try each question before revealing its explained answer. Use the explorer to test a procedure on the original course data.
REAL COURSE DATA · FOLLOW THE PROCEDURE
Find Mathematics marks below the final average
Read the current record, check the explanation, and watch the variables. Use Back to revisit any step.
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Start at the first step. Watch the current row and the values we remember.
Mixed practice
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Is a column one student or one attribute?
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One attribute, such as Mathematics. A row describes one student.
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Which field tells you the length of considered?
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LetterCount, which is 10. SerialNumber 12 is its position identifier.
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What does adding ₹567 on every item row produce?
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₹3,969, which wrongly counts the same bill seven times.
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Does a Mathematics mark of 72 pass the below-average test here?
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Yes. 72 < 2171/30.
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How many of 50,50,50,100 lie below their mean?
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Three. Their mean is 62.5.
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Why can the first mark update both min and max?
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Before seeing any marks, both limits are placeholders. The first real mark is both the smallest and largest seen so far.
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Is Monday short under this definition?
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No. Six letters makes it long; it is the frequent-long counterexample.
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Does 8/9 prove that short words cause repetition?
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No. It describes an association in this dataset, not a causal rule.
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Who has the highest actual total?
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Rahul, CardNo 11, with 281.
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Current values are 90,80,70. What happens when 95 arrives?
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Third becomes 80, Second 90, First 95. Save lower slots first.
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What is the third distinct Mathematics level here?
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89. The third student score counting ties is 93.
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What does return Sum do?
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It sends the computed Sum back to the code that called the procedure.
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What is the sum of subject maxima?
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97+92+97=286.
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Why store each procedure result in a separate variable?
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Later calls return new answers. Saved variables keep all four values available for the final comparison.
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What happens if you move SecondTotal but forget SecondID?
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The score can become attached to the wrong person.
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Can four first-place ties all fit three prizes?
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No. The rules need a tie policy or permission to award more than three prizes.
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Do the actual winners satisfy the lecture’s representation rule?
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Yes. Rahul is M; Deepika and Abirami are F.
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Does renaming a reversed pile restore sequence?
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No. It returns the cards but preserves the reversed sequence.
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What is the difference between interface and implementation?
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The interface is the agreement the caller relies on. The implementation is the internal method used to meet it.
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Must every procedure return a useful number?
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No. Some procedures act by updating or rearranging data.
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How many bills exceed the final average?
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8 bills.
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What are the final Big Bazaar sum and count?
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₹13,284 and 6 bills.
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Must a nonmatching bill reset the counters to zero?
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No. It should return the existing values unchanged.
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A sum procedure returns the correct answer but reverses a text table. Is that necessarily safe?
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No. A caller may require preserved order. Correct results do not excuse a contract-breaking side effect.
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For distinct top levels 90,80,70 and new 85, what are the new levels?
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90,85,80. Move old Second 80 into Third before writing Second 85.
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Can a common subject topper be inferred solely from the sum 286?
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No. Compare the maximum actual total with 286. Here 281 differs, so there is no common topper.
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How many visits does the below-average algorithm make on 30 rows?
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60 record visits:30 for the sum/count scan and 30 for the filter scan. Phase-boundary steps are not extra record visits.