anybody in this class that can help me and my roommate out on some of the webassigns??? we are stuck on 1.5 question 2...? thanks

9/7/2006 2:38:15 PM

whats the question, i took ma 114 like 2 years ago

9/7/2006 3:08:49 PM

um, i'll post it, its pretty long

9/7/2006 3:18:00 PM

The trees in a forest are grouped into the following age groups:

Group 1 = trees 0-10 years old (seedlings and very small trees)
Group 2 = trees 10-20 years old
Group 3 = trees 20-30 years old
Group 4 = trees older than 30 years (i.e. mature trees)

Each decade 90% of the trees in Group 1 die, i.e. only 10% survive. (Think about how many oak seedlings you see under a large oak tree. Most of them never grow up to be a mature tree because the forest simply doesn't have room for that many trees.) And during the decade the small trees in Group 1 don't produce any new trees because they are too young.

Each tree in Group 2 produces on average 11 new seedings (Group 1 trees) during a decade of time. And during the decade 60% of the trees in Group 2 survive. (The larger a tree gets, the better its chances of growing into a mature tree.)

Each tree in Group 3 produces on average 15 new seedings (Group 1 trees) during a decade of time. And during the decade 75% of the trees in Group 3 survive.

And finally, each tree in Group 4 (the mature trees) produces on average 50 new seedings (Group 1 trees) during a decade of time. And during the decade 92% of the trees in Group 4 survive.

Let's suppose that we're starting with a forest that has been thinned of all its young trees, so there are no trees in Groups 1, 2, or 3. And let's suppose we start with 800 mature trees in Group 4.

Put all this information into a 4x4 matrix which shows the population dynamics of this forest over the course of a decade.

Let's look at the 3rd row of your matrix, for example. The 3rd row should show how many trees in each category result over the course of a decade from a typical tree in Group 3. (Hint: Each Group 3 tree will produce some seedlings, and some of the Group 3 trees will survive the decade. This implies that row #3 of your matrix will have a nonzero number (information found in the data above) in column 1 and in column 4. However, a Group 3 tree can't possibly produce a Group 2 tree in the course of a decade, nor can it remain a Group 3 tree itself because it ages into Group 4 during the course of the decade. So the entries in columns 2 and 3 will be zero for those reasons.)

[Comment: In answering the following questions, keep in mind that this is an "approximate" model. For example, if you have 25 trees and say that 1/2 of them survive, you're talking about 12.5 trees. What do 12.5 trees look like? There's no such thing as half a tree. So what do you do if you come up with an answer that predicts 329.7 trees after a decade has passed? It really doesn't matter. Keep in mind that WebAssign generally accepts numerical answers that are accurate to within 1%. So WebAssign would count your answer as correct whether you enter 329.7, 329, or 330. But in general you can't go wrong by entering "too much" accuracy unless a question specifically calls for a whole number as the answer. So I'd suggest you go ahead and enter 329.7 in a case like this.]

After one decade, how many trees will we have in each category?

# trees in Group #1 = _____
# trees in Group #2 = 0
# trees in Group #3 = 0
# trees in Group #4 = 736

After two decades, how many trees will we have in each category?

# trees in Group #1 = ____
# trees in Group #2 = ____
# trees in Group #3 = 0
# trees in Group #4 = 677.12

After three decades, how many trees will we have in each category?

# trees in Group #1 = ____
# trees in Group #2 = ____
# trees in Group #3 = ____
# trees in Group #4 = 629.95

After four decades, how many trees will we have in each category?

# trees in Group #1 = ____
# trees in Group #2 = ____
# trees in Group #3 = ____
# trees in Group #4 = ____

[Edited on September 7, 2006 at 3:21 PM. Reason : the numbers are ones i got right, the blanks are ones i cant get]

9/7/2006 3:18:26 PM

so i'm guessing that 5 isnt the answer to the first question(1 decade group 1 trees)

[Edited on September 7, 2006 at 3:41 PM. Reason : thats the obvious answer in my opinion, which is why i think its wrong]

9/7/2006 3:39:37 PM

this is the first time a MA 114 question thread has went 2 posts without some smartass saying "hey man that class is so damn easy blah blah blah cats dicks"

9/7/2006 4:09:29 PM

yeah, 5 is wrong, thats the first thing i thought too

9/7/2006 4:11:57 PM

I can help you later tonight when I get home if you still haven't figured it out. I have already done that question.

9/7/2006 5:01:57 PM

ok thanks a lot man, jsut send me a message or something

9/7/2006 5:36:11 PM

bttt

9/8/2006 3:22:49 PM

could someone possibly help me on #2 also?

9/8/2006 10:59:11 PM

Does anyone still need help on any problems?

9/9/2006 12:08:03 PM

Has anyone done the Homework 5.1 yet? I am having trouble with the tennis match problem where it suggests that you draw a tree diagram to figure out the total # of outcomes.
-------------------------------------------------------
For each of the following situations, list the number of outcomes in the sample space.

A tennis match is played where the winner must win 3 sets to win the match. (Think of the outcomes in terms of a tree diagram).

Number of possible outcomes =

10/31/2006 1:17:37 AM

How did everyone think the test was?

11/1/2006 8:03:51 AM

I got an 82, i was working on an 8 pt question as time expired, it was one of those easy initial siplex tableua problems too, damn

11/1/2006 3:11:23 PM