MCQ Review

Score: 54/70

Questions I got wrong:

1.1 Program function and purpose 1.4 Identifying and Correcting errors 2.4 Using Programs with Data

My first MC:

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Topics I had trouble with:

This time, it was more scattered, with questions missed from various topics

Questions I missed in both MC’s:

  • algorithm efficiency and runtime
  • binary search

Things that I improved on:

  • NAND logic gates
  • completing code and using if statements
  • citizen science

Longest Questions:

This time, I gave myself the two hours college board allows in order to simulate what it would be like on the test. The maximum time I spent was 4 minutes on strings, and I finished with extra time left over. This means that I need to focus on accuracy rather than speed.

Quiz Corrections:

Consider the two programs below. The figure presents two programs, labeled Program A and Program B, each with two blocks of code that consist of 4 lines. Throughout the second block of code in each program there are nested blocks of code, as follows.

Which of the following best compares the values displayed by programs A and B? My answer: Program A and program B display the same number of values, but the values differ. Correct answer: Program A and program B display identical values in the same order. Explanation: The two programs aren’t in the same order, but they both display the numbers from 1-10.

Which of the following observations is most consistent with the information in the circle graph?

My answer: Over 75% of the files stored are at least 100 KB in size. Correct answer: Over 75% of the files stored are 10 MB in size or less. Explanation: The files at least 100 KB are only 59%, while the files up to 10 MB are 76%.

In the following program, assume that the variable n has been initialized with an integer value. The figure presents 2 blocks of code that consist of 14 total lines. Throughout the code there are nested blocks of code. Which of the following is NOT a possible value displayed by the program?

My answer: too low Correct answer: out of range Explanation: Correct. The string ”out of range” could only be displayed if the condition n ≥ 1 was false. If the initial value of n is at least 0, then n will be incremented by 1, making n at least 1. Therefore the condition n ≥ 1 will be true and ”out of range” will not be displayed. If the initial value of n is negative, then n will be multiplied by -1, making n at least 1. Therefore the condition n ≥ 1 will be true and ”out of range” will not be displayed.

Which of the following best explains how a certificate authority is used in protecting data?

My answer: A certificate authority certifies the safety of a particular Web site so that users know that it does not contain any viruses. Correct answer: A certificate authority verifies the authenticity of encryption keys used in secured communications. Explanation: Certificate authorities issue digital certificates that certify the ownership of public keys.

The procedure BinarySearch (numList, target) correctly implements a binary search algorithm on the list of numbers numList. The procedure returns an index where target occurs in numList, or -1 if target does not occur in numList. Which of the following conditions must be met in order for the procedure to work as intended?

My answer: The list numList must not contain any duplicate values Correct answer: The values in numList must be in sorted order. Explanation: Correct. In order for a binary search on a list to work as intended, the list must be sorted.

Consider the following algorithms. Each algorithm operates on a list containing n elements, where n is a very large integer.

  1. . An algorithm that accesses each element in the list twice
  2. An algorithm that accesses each element in the list n times
  3. An algorithm that accesses only the first 10 elements in the list, regardless of the size of the list

    Which of the algorithms run in reasonable time?

    My answer: 3 only Correct answer: 1, 2, and 3 Explanation: for an algorithm to run in reasonable sum, it has to take a number of steps less than or equal to a polynomial function. 1 accesses elements 2n times, 2 accesses n^2 times, and 3 accesses 10 elements.

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