Unit 1 Self-Check Questions

1.2.3

AAP-2.D

Which two of the following sentences could be reported by gossip?
gossip: (report (join (who) ( ) (does what) ( ) (who)))

For reference:
who reporter block definition: report (item (random) of (list (Señora) (Ms. C) (my cat) (Hannah) (Jake)))

does what reporter block definition: report (item (random) of (list (listened to) (loves) (ran away from) (helped) (is in a band with)))

Señora and Ms. C helped.

It's true that there are two people (two "who"s) and one action (one "does what"), but they aren't in the right order. Also, the word "and" isn't anywhere in the program.

Señora ran away from my cat.

Correct! This follows the pattern: "who," "does what," "who."

Hannah listened to Hannah.

Correct! This follows the pattern: "who," "does what," "who."

Jake helped.

This sentence is missing the second "who."

1.2.5

AAP-3.E

more complicated who {
if (pick random (1) to (4)) = (3) {
report (join (who) (', who') (does what) ( ) (who) (,))
} else {
report (who)
}
}

About how often will more complicated who pick the more complicated choice?

Half the time

If a number is chosen randomly from 1, 2, 3, and 4, about how often will that number be 3?

A third of the time

If a number is chosen randomly from 1, 2, 3, and 4, about how often will that number be 3?

A quarter of the time

Correct!

Three quarters of the time

If a number is chosen randomly from 1, 2, 3, and 4, about how often will that number be 3?

1.2.5

AAP-3.E

Here is the script inside more complicated who. What change to this script will make the more complicated phrase appear more often?

Change the 4 to 5.

Then three will be the randomly chosen number one out of five times instead of one out of four, and so we'll have a complicated subject less often.

Change the 4 to 3.

Correct! Three will then be the chosen number one out of three times, and so we'll have a complicated subject more often.

Change the 3 to 1.

1 is just as likely a random choice as 3, one out of four times, and we'll have a complicated subject just as often as before.

Change the 3 to 5.

The chosen number can never be 5, so we'll never get a complicated subject.

1.2.5

AAP-3.E

Click for a review of odd and even numbers.

An even number is an integer that is divisible by 2 (such as 2, 14, 0, -4, -6, -28, and -176).

In contrast, odd numbers are integers not divisible by 2 (such as 1, 3, 9, 17, -5, -33, and -221).

Which expression will return a random even number between 1 and 10?

RANDOM(2, 10)

RANDOM(2, 10)

will return 2, 3, 4, 5, 6, 7, 8, 9, or 10.

2 * RANDOM(1, 5)

Correct!

RANDOM(1, 5)

will return 1, 2, 3, 4, or 5, and so

2 * RANDOM(1, 5)

will return 2, 4, 6, 8, or 10.

RANDOM(1, 10) / 2

RANDOM(1, 10)

will return 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10, and so

RANDOM(1, 10) / 2

will return ½, 1, 1 ½, 2, 2 ½, 3, 3 ½, 4, 4 ½, 5.

RANDOM(1, 5)

RANDOM(1, 5)

will return 1, 2, 3, 4, or 5.

1.2.5

AAP-3.E

Which expression will simulate the rolling of two dice?

RANDOM(1, 6) + RANDOM(1, 6)

Correct!

RANDOM(1, 6)

will return 1, 2, 3, 4, 5, or 6 with equal probability, simulating one die, and so

RANDOM(1, 6) + RANDOM(1, 6)

will return 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12 with the same probability as two dice.

2 * RANDOM(1, 6)

You have the right idea, using

RANDOM(1, 6)

for the roll of a single die. But this expression doesn't roll two dice; it rolls one die and doubles the result. So

2 * RANDOM(1, 6)

will only return 2, 4, 6, 8, 10, or 12.

RANDOM(2, 12)

RANDOM(2, 12)

will return 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12 equally often. Do you score 2 rolling two dice as often as you score 6?

RANDOM(1, 12)

Can you score a total of 1 by rolling two dice?

Unit 1: Introduction to Programming

Lab 2: Gossip