Question

Check my answers please! (:

Identify each sample, suggest a population from which it was selected, and state whether it is unbiased (random) or biased. If unbiased, classify the sample as simple, stratified, or systematic. If biased, classify as convenience or voluntary response.

1. At a town council meeting, the chair asks 5 citizens attending for their opinions on whether to approve reasoning for residential area. ==> convenience

Answer 1

2. To determine the extent of leaf blight in the maple trees at a nature preserve a botanist divides the reserve into 10 sections, randomly selects a 200-foot by 200-foot square in the section, and then examines all the maple trees in the section. ==> Stratified

Answer 2

3. To determine the popularity of online banking in the United States, a polling company sends a mail-in survey to 5000 adults to see if they bank online, and if they do, how many times they bank online each month. ==> random

4. A shoe manufacturer wants to check the quality of it's shoes. Every 20 minutes, 20 pairs of shoes are pulled off the assembly line for a thorough quality inspection.==> systematic

5. To learn which benefits employees at a large company think are most important, the management has a computer select 50 employees at random. The employees are then interviewed by the Human Relations department. ==> Random

6. An insurance company checks every 100th claim payment to ensure that claims have been processed correctly. ==> systematic

Answer 3

They are asking for two things, so you need to list both. For example:
#1, biased, convenience

Which is correct. Also, random is not one of the answers. It is sort of half an answer.

Answer 4

Okay so #2 would be unbiased and stratified?

Answer 5

and #3 would be unbiased but I don't know the second half... can you please explain?

Answer 6

#2, he is grouping them by area, not by type of tree, and sampling inside the area. So that is a cluster rather than stratified.

Answer 7

so its simple?

Answer 8

#3, they are going after adults, so it is not strictly random. However, I am not sure it is biased enough to qualify as convinience... hmm... and it does not seem like stratification because there are not different groups. I can see why you find that one hard!

Answer 9

Haha! Yeah! I was like whaatt? An i asked my mom and she tried figuring it out but she couldnt then i asked my dad and he couldnt...

Answer 10

#2 He is still doing a type of grouping, but cluster rather than stratified. Cluser is where you group things phisically somehow then do random inside the areas.

#4 correct

#5 simple random

#6 correct

Answer 11

but cluster wasnt an answer?

Answer 12

Ooops. Sorry. Hmmm.... we gee. They went and used one they ddn't list as an answer! LOL.

Answer 13

lol

Answer 14

I did a little digging. Looks like cluster is somewhat related to stratified.

http://pages.csam.montclair.edu/~mcdougal/SCP/Sampling.htm

Answer 15

okay. so could i be able to put stratified?

Answer 16

Yah, I would say of those answers it is the best choice.

Answer 17

okay so:
1. biased, convenience
2. unbiased, stratified
3. unbiased, simple, random
4. systematic
5. unbiased, simple, random
6. systematic

Answer 18

3. To determine the popularity of online banking in the United States, a polling company sends a mail-in survey to 5000 adults to see if they bank online, and if they do, how many times they bank online each month.

They do not say how this poling company picked the adults.... it is not fully random if they somehow know they are adults... but I think it is not biased enough to be called biased. So I think your original answer is the best choice: Simple random.

Answer 19

4&6, Unbiased, systematic, but yah.

Answer 20

okay! (:

Answer 21

Can you do a run-through of the answers please so that I can just make sure what i have written down is what we wrote down at the top?

Answer 22

Why I thouhgt it was cluster on that one is simple: You divide things up into clisters, pick one cluster at random, then look at everything in that cluster. With the tress, that is exactly what they described.

Answer 23

unbiased and
simple (Trly random, but can randomly pick a not so representative group)
stratified (Split into clear groups, pick randomly from each group. That way all groups are represented.)
systematic (Every set number. The duck, duck, goose method.)

biased and
convenience (They were there. Eay to get them)
voluntary response (They picked you)

For those, yah, I agree it would be:

1. biased, convenience
2. unbiased, stratified
3. unbiased, simple random
4. unbiased, systematic
5. unbiased, simple random
6. unbiased, systematic

Answer 24

Thank you so much! (: Your the best!

Answer 25

That page I lined has a nice way of putting it. Might be easier than the book you have or notes, so mught want to give it a quick look over.

And don't have too much fun here!

Answer 26

haha! I booked marked the page because it explains way easier than my book! Thank you!!! I wont have too much fun! lol(;

Answer 27

Yah, sometimes books get waaaay too technical. You need a manual for how to read those books!