Statistics help needed

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statisticsisawesome

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Can I please have some more help?
For the following statement about a statistical survey, identify the following items (if possible). If you can’t tell,
then say so – this often happens when we hear or read about a survey.
A recent online poll conducted by an Australian newspaper of 1083 registered voters found
that 43% of the respondents believe it is likely that bushfires are linked to climate change

a) The possible population of interest
Registered voters

b) The population parameter
Proportion of registered voters who believe it's likely that bushfires are linked to climate change

c) The sampling frame
Not stated in the question

d) The sample
1083 registered voters

e) The sampling method, including whether or not randomisation was employed
voluntary response sample

f) Who (if anyone) was left out of the study
People who didn't participate in the study

g) Any potential sources of bias you can detect and any problems you see in generalising to the population of
interest
People are more likely to participate in the survey if they have a strong opinion towards either side. What source of bias would this be?

Can someone please tell me if my answers are correct?
 
Your work looks good. Parts a and b look right. In part c, it's true the sampling frame is not stated, but you could guess the group of
people forming the population from which the sample is taken so you could put that at the end of what you wrote. Parts d and e are right. Part f is asking for people that could not possibly have been in the study since it was an online survey conducted by an Australian newspaper. Think about who is left out because it is online and who is left out because a parrticular newspaper doe the survey. The first sentence of part g is good . You would have to guess the direction of the bias. Are there more people who would have a strong feeling in the "yes' group or the "no" group?
 
Thanks
with part f, can I say it's people who didn't participate in the survey, and also people who don't have access to internet?
and with part e, would I be correct in saying that randomization is not used?
What type of bias would part g be?
 
In part f, you are right to say people who do not have access to the Internet because they could not possibly be in the survey. As for the other part, there are some people who saw the online survey, but decided not to do it. They are not really left out because they had a chance to do it. But aren't there other people who have access to the Internet and never see the survey? Those people are left out of the study.

Undercoverage bias is when some groups of people are left out of the survey even though it is supposed to represent them (reegistered voters in this case). Check if that is the term that has been used in your class.
 
Prof said:
In part f, you are right to say people who do not have access to the Internet because they could not possibly be in the survey. As for the other part, there are some people who saw the online survey, but decided not to do it. They are not really left out because they had a chance to do it. But aren't there other people who have access to the Internet and never see the survey? Those people are left out of the study.

Undercoverage bias is when some groups of people are left out of the survey even though it is supposed to represent them (reegistered voters in this case). Check if that is the term that has been used in your class.
Click to expand...
So with part f, would the people left out be both people who didn't participate in the survey AND people who don't have access to internet??
 
I am assuming that you teacher saying "left out" means those who had no chance to join in. If that is not correct, then your answer that you just wrote would be right. (See if you have any example in the book or in your notes where "left out" is used because it is not a standard statistical term.) I am guessing that "left out" means people who had no chance to be in the survey. Then, the answer is the people who went on the Internet and did not see the survey AND the people who don't have access to the Internet. (In my interpretation, you don't want to include people who went on the Internet and saw the survey but decided not to do it because they are not really "left out.")
 
In part e, you are right that randomization is not used. People decide for themselves whether to participate (if they see the survey) rather than the researcher picking people at random to participate.
 
Prof said:
In part e, you are right that randomization is not used. People decide for themselves whether to participate (if they see the survey) rather than the researcher picking people at random to participate.
Click to expand...
Thanks, and in part e is the sampling method a voluntary response sample?
 
Yes, part e is a voluntary response sample. I will not be tutoring again until Tuesday. You are welcome to submit questions for other tutors to answer.
 
You post your question and any tutor who is working can read it and answer it. I have never met any of the tutors. Have a good weekend. I am signing off.
 
2.2 What’s the design?
Read the brief description related to a statistical study below, and
Runners recovering from lower leg fractures were randomly allocated to three different training programs. Half of each group also followed a high calcium diet. Bone density measurements were taken for all subjects. Also:

a) explain why it is an experiment rather than an observational study.
It is an experiment since we apply treatments to the group and record the effects. In this case, the recovering runners were allocated to the training programs and half of each group followed a high calcium diet, and the bone density measurements were taken for all subjects

b) identify the factor(s) in the experiment and the number of levels for each.
training programs is the factor, and it has 3 levsls
high calcium diet is the factor, and it has 3 levels


c) give the total number of treatments.
2

d) state the response variable(s) measured.
bone density measurements

e) explain whether it was blind, or double-blind
Not sure of this one
Can someone please verify if my answers to part a,b,c and d are correct?
And have I have help with part e?
Thanks
 
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