Project Stem AFE CS Unit 4 Review Test

What are the values of the variables a and b after the Python program below has been executed?

• a = 5 and b = 10

• a = 10 and b = 5

• a = 5 and b = 5

• a = 10 and b = 10

The following images show the same image, but one of them is compressed and the other is not.

• The image on the left is compressed and the image on the right is the original.

• The image on the right is compressed and therefore it has a larger file size than the original image on the left.

• The image on the left is compressed and therefore it has a smaller file size than the original image on the right.

• The image on the left is the original image and the image on the right is compressed.

While writing a program to regulate the speed of a self-driving car, you find that your software sometimes miscalculates the ideal car speed for city streets to be over 1500 MPH (nearly twice the speed of sound), when it should be approximately 30 MPH. Which of the following strategies would be most efficient to employ in debugging your program?

• At the very end of the speed calculations, add an additional line of code that divides the calculated speed by 50 so that the program never produces such high speeds.

• After each calculation within your program, insert a temporary statement that displays the most recently calculated value. When running your program, compare the displayed values with the expected values to identify where in the program the error is being introduced.

• Starting at the end of your program and working backward, systematically delete each line of code that relates to calculating and re-run the program after each deletion to identify where in the program the error is being introduced.

• Delete all of the code relating to speed calculations and rewrite it again.

Consider the following procedure called square that is meant to multiply a number by itself and return the value. What should go in place of Missing Instructions in order to make this procedure work as intended?

• number -- number * number

• squared -- number * number

• square -- number * number

• squared -- number * 2

Which of the following Python code segments best matches this Scratch block?

• x = 0 if x > 0: x = x - 1 else: x = x + 10

• int x = 0; if (x > 0) { x = -1; } else { x = 10; }

• x = 0 if x > 0 x = x - 1 else x = x + 10

• x = 0 if x > 0 { x = x - 1 } else { x = x + 10 }

Which of the following describes a lossy transformation of a digital image composed of pixels which have red, green, and blue components stored using values from 0-255?

• Replace the green component of each pixel with the average value of the red and blue components of the pixel.

• Replace the values for each pixel with the values from the pixel which is 10 pixels to the right. If the pixel is less than 10 pixels from the right of the image, continue counting from the left of the image when the edge is reached.

• Swap the values of the blue and green components for each pixel.

• Replace each component of each pixel with the original value of that component subtracted from 255.

A graphic designer is hired to create a new logo for their client. The client provided the following guidelines, listed in order of precedence:

• The logo needs to have clean lines, even when scaled to different sizes
• The logo must use only a few colors
• The final logo size must not be large

Based on these guidelines, which type of image should the graphic designer create?

• PNG

• JPG

• SVG

• GIF

The following procedure check is called in a program when a user answers a True or False question, with the answer typed by the user being assigned to the answer parameter. If the user types in 'True True False True' as their answers for four questions on a quiz, how many times will the procedure check display Correct?

• 1

• 2

• 3

• This cannot be determined from the information given

Consider the following algorithm for manipulating the individual pixels of a digital RGB image of a panda bear surrounded by dense green jungle foliage. Algorithm: For each pixel, swap the values in the green and blue channels, leaving the red channel alone. Which of the following best describes the resulting image?

• The panda’s fur will appear red and black.

• The foliage will appear green, but the panda’s fur will appear blue and black.

• The panda’s fur will appear black and white, but the foliage will appear to be tinted blue.

• The resulting image will look identical to the original, unmodified image.

Procedures in programming are often defined with parameters - variables that are used in the procedure for which a value needs to be specified each time the procedure is called. Which of the following give a variable that would be useful to have as a parameter for the specified method?

I. The value of 𝜋 (pi) in a procedure to find the area of a circle

II. The name of an author in a procedure to search a library catalog for books

III. The side length of a cube in a procedure to find the surface area of a cube

• I only

• II and III only

• I and III only

• II and III