Identify the bias in each sample. a) A phone-in radio show asks callers their opinion about the city's baseball team not making the playoffs the day after they are eliminated. b) To learn which team Canadians feel will win the stanley cup, researchers call 100 people from ottawa. c) To find the age that most canadians feel should be the legal driiving age, researches ask 3000 high school students.
please help me someone : (
\[a) voluntary response bias b)inadequate sample size c) \]
c)..?
i didnt understand b ..!
meaning it's biased because it didn't adequately... ok. what I said was wrong. I think it is basically convenience sampling.
i guess your right
the third one is i think exactly the same reason.
so third one is convenience sampling too?
that's my guess
next question it says that . Sugeest a way to reduce the bias in each sample in this question
a) stratified random sampling b) stratified random sampling c) two stage cluster sampling
can i ask you a question?? what does bias mean .. like i dont get it
bias is like somebody is going to respond that way, ur data will be skewed, for example:
if u go to a rich neighborhood and ask them whether rich ppl should pay more taxes,
they will say NO, and if u go to a poor neighborhood and ask whether rich ppl should pay more taxes ppl are more likely to say yes... So both responses are biased
Basically u give a biased response if u get something sort of like profit from it..
o okay :) i get it
basically bias is when the sample mean is different from the true population mean
so why biased sample may not produce accurate results?
because you won't get accurate results..
because of methods you use
woops sorry lol, I meant because biased data is just like BSed data
ill let moo explain it lol I've never been good at stat.. Any calculus questions?
can u help me with statistic questions?
?? please"
i can try..
One way to judge the sucess of a movie is to rank it by ticket sales. however, tickets are more expensive today and theatres hold more people than in the past. suggest a way to remove these biases so that past and present movies can be compared fairly.
well the top option would be make the tickets cheap.
ok??
Not free, because then rich people would think that this movie is trash which is why they are giving away the tickets.. so you would only get responses from the rich
*sorry meant: Not free, because then rich people would think that this movie is trash which is why they are giving away the tickets.. so you would only get responses from the poor people who would take the tickets
and if the ticket prices were high, then poor people wouldnt be able to afford them and you would get responses from only rich people
and to minimize bias you want responses from both rich and poor people, u need diversity
oh okk :)
can i ask next q?
sure..but i am pretty bad at stat if i can't do it then sorry..
sure :)
its just that my stat teacher was really bad, but i will attempt ur question
ok
a popular television sports show asked people to phone in their pick for the NBA Most Valuable player. with 30 min left in the show, they announce the result to that point. a) how might this announcement affect the outcome of the survey? b) Does reporting the early results make the survey biased? explain why or why not?
Okay first of all a) you will definitely get biased results, and you always want to avoid them.
b is easy
b) Reporting survey earlier would decrease the bias because look, it is the end of the game right, and suppose you were going to vote for player A, but turns out player B scored more goals or whatever u call em in basketball (sorry i hate american sports), so you will end up picking player B if you choose when there's 30 mins left..
And if you are reporting it early, then player A and B would have equal chances, because you don't know who is going to perform better..
ooo
do you kind of get it? If nothing affected your vote then it would NOT be biased, but halfway into the match, you see one guy is better than the other, so something is affecting your vote
next question is : Melissa asks five of her friends about their favourite type of movie. Four say their fav is comedy. She reports that 80% of teenagers prefer comedies over all other movie types. explain two flaws in her survey.
her sample size is too small..
or not sample size, i mean whatever you call it, you can't get sufficient data from only 5 people
okay it is called a sample size, just looked it up lol
lol
so now she should NOT have asked her friends who are each others' friends too, because most friends share common tastes, so they all would like comedies, or tragedies or whatever..
i mean friends tend to have same tastes don't they.. all of my friends like math lol ..well sorta..
yea right :P
any more?
A local soccer league wants to give its players a bonus: either free soccer balls, free movie tickets , ir coupons for the snack bar. a) Design a survey the league can use to decide which bounus to offer. b) how can the data be collected? c) is it possible to survey the whole population?? explain?
??
thinking..
ok
uhmm i dont get it what is the survey about? do we have to ask whether they want one of those options? either free soccer balls, free movie tickets , ir coupons for the snack bar?
yessss i gues we need to ask :S
well i guess for part A: We could either mail them letters or something asking what they would prefer, or email them or call them, etc.. B: Let soccer balls be 1 tickets - 2 coupons - 3, ask whichever they prefer and record the number then see how many counts of each number we have..
C: It is never possible to interview the whole population, because some people will think its a scam and not respond, others will just think that its a joke or something and just respond with a random number without actually thinking about what they want..
post the next one..
explain the difference between response bias and non- response bias. b) are two biases opposites? explain. c) Giv an example of each.
THIS CALLS FOR SOME GOOGLINGG!! LOL afk.. lookin
hahaha :P man google dosnt make any sense :P coz i need to understand what it is :P lol
Non response bias is NOT the opposite of response bias.. that's as much as i know so far..
okay I know what a response bias is: It occurs when the survey takers says something that he or she thinks the surveyor wants to hear from them.
For example: A teacher asks the kids DID YOU DO YOUR HOMEWORK??? Kids will respond of course we did, because they think they will get punished otherwise..
that's response bias..
o
non response is basicaly oppsite of that .. right?
no its not
outch
so that's half of part a and c so far, let me understand what non response bias is..
Okay non response bias is basically when you don't respond
thats what i said lol
well u don't DON'T respond just because u think u will be punished or lose something..
is tht it?
no, imagine this
did u answer b ??
yeah thats b
they are not opposites..
c) Response bias: teacher : "did u do ur hw?" kids: "yes" even though maybe they didnt Non- response bias:
Imagine a guy standing on the corner of Lexington ave and 23rd street in manhattan asking college kids rushing by whether they want to take a survey.. Most of them including me would say NO, simply because they don't have time..
Lex and 23rd is crazy.... especially durin breaks in b/n classes...=(
so that's C, now for A
u told me a already dude
oh okay.. =)
sorry im like helpin 3 ppl, hard to keep track... im such a nerd -_-...
i should be enjoying life, but here i am stuck helpin others, i think i should log off...
holy ship 92 replies? *this is 93rd..
heyy thankyouu soo much.. i was writing the answer :SS :) ur really halpful thanks a lot
ready to help with math only... maybe I should become a math teacher lol, I hate teaching and tutoring, but somehow im okay at it..
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