Statistics question

[statisticsisawesome]

2.8 A survey on the drinking habits of adults asked the participants how many days a week they consumed alcohol, as well as the type and quantity of alcohol consumed. Of the 755 adults surveyed, 491 said they consumed alcohol at least twice a week
a) Create a 95% confidence interval for the true proportion of adults who consume alcohol at least twice a week, and interpret the interval
P hat = 491/755
therefore Q hat = 264/755
(491/755) - 1.96*sqrt(((491/755)*(264/755)))/(755))) < P < (491/755) + 1.96*sqrt(((491/755)*(264/755)))/(755)))
= 0.616315509 < P < 0.684346743
therefore we are 95% confident that between 61.63% and 68.44% drink alcohol atleast twice a week

b) Based on your confidence interval, comment on the accuracy of a media report stating that 70% of adults consume alcohol at least twice a week.
Not very accurate since 70% is not within the confidence interval (61.63%, 68.44%)
Can someone please verify if my answers for the above question are correct?
Thanks

 

[Prof]

Your work looks good! Your confidence interval is correct. In your conclusion to part a, you could say ... 68.44% of all adults... to make it clearer.
In part b, your answer is pretty good. You could say, "it is probably not accurate" insteaad of "not very accurate".

 

[statisticsisawesome]

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?