True or false: the following matrix is a legit Leslie matrix for demographic population ecology.

 

Question 1

2 / 2 pts

True or false: the following matrix is a legit Leslie matrix for demographic population ecology.

Correct!

 

True

 

 

False

 

 

Question 2

2.5 / 2.5 pts

Suppose a certain species is modeled with the following Leslie matrix:

If, in the first year, the population consists of 10 newborns (i.e., one-year-olds), 10 two-year-olds, and 10 three-year-olds, how many two-year-olds will there be next year?

Correct!

Correct Answers

10.0 (with margin: 0.0)

 

Question 3

2.5 / 2.5 pts

Suppose a certain species is modeled with the following Leslie matrix:

If, in the first year, the population consists of 10 newborns (i.e., one-year-olds), 10 two-year-olds, and 10 three-year-olds, how many three-year-olds will there be in two years?

Correct!

Correct Answers

5.0 (with margin: 0.0)

 

Question 4

3 / 3 pts

A friend wants to send you a four-bit message using a Hamming encoding scheme. When you receive his transmission, the bits you receive are as follows:

1100110

What is his four-bit message?

Correct!

Correct Answers

0110

 

0,1,1,0

 

0, 1, 1, 0

 

[ 0, 1, 1, 0 ]

 

[0, 1, 1, 0]

 

[0,1,1,0]

 

(0,1,1,0)

 

(0, 1, 1, 0)

 

( 0, 1, 1, 0 )

 

 

Question 5

3 / 3 pts

Now he sends another 4-bit message. When you receive his transmission, the bits you receive are:

0001000

What is his four-bit message this time?

Correct!

Correct Answers

0000

 

0 0 0 0

 

0,0,0,0

 

0, 0, 0, 0

 

[0000]

 

[0,0,0,0]

 

[0, 0, 0, 0]

 

[ 0,0,0,0 ]

 

[ 0, 0, 0, 0 ]

 

(0,0,0,0)

 

(0 0 0 0)

 

( 0, 0, 0, 0 )

 

 

Question 6

1 / 1 pts

If you give me the adjacency matrix A for a graph, then to find the number of distinct paths from node i to node j of length 5 or less, I compute A⁵ (i.e., A to the fifth power) and look at entry [i,j] of that matrix.

 

True

 

Correct!

 

False

 

 

Question 7

1 / 1 pts

If you give me the adjacency matrix A for a graph, then to find the number of distinct paths from node i to node j of length 3 or less, I compute A³ + A² + A, and look at entry [i,j] of that matrix.

Correct!

 

True

 

 

False

 

 

Question 8

4 / 4 pts

Consider the following graph:

Which of the following are true about its adjacency matrix? Check all that apply.

Correct!

 

It is a square matrix.

 

 

It has 5 rows.

 

Correct!

 

It has 7 columns.

 

Correct!

 

Its entries are all 1’s and 0’s.

 

Correct!

 

It has 0’s all along the main diagonal.

 

 

It is upper-triangular (at least under some permutation of the rows/columns).

Correct!

 

It is block diagonal (at least under some permutation of the rows/columns).

Correct!

 

It is symmetric, no matter how the rows and columns are ordered.

 

Correct!

 

The largest row sum (i.e., the largest total of the entries in any given row) is 3.

 

The smallest row sum (i.e., the smallest total of the entries in any given row) is 2.

 

Question 9

1 / 1 pts

What did you think of the “dab” Stephen did at the very beginning of allthemath.org Volume Two Episode VI? (You will receive full credit for this question just by answering it, even if your answer doesn’t match mine.)

 

zomg soooooo cool wow

 

Correct!

 

not bad, but you could use more practice

 

 

tbh, you’re kind of old to be doing that sort of thing

 

 

Umm….