Interactive practice questions
A random survey was conducted to estimate the proportion of people who favoured reading using an e-reader over a standard book. It was found that $286$286 out of $419$419 people surveyed preferred the e-reader.
Determine the sample proportion $\hat{p}$^p of those in the survey who preferred to use an e-reader.
Working with a two-sided confidence interval of $90%$90%, estimate the minimum sample size necessary to ensure a margin of error of at most $0.05$0.05 if the sample proportion remains the same.
Using the sample proportion $\hat{p}$^p from the initial survey, the $95%$95% confidence interval for $p$p is $0.64\le\hat{p}\le0.72$0.64≤^p≤0.72.
Considering this interval, which of the following surveys are more likely to be representative of the total population?
A random sample of $79$79 at a book store found that $31$31 had a preference for e-readers.
A random sample of $365$365 at an inner city park found that $256$256 had a preference for e-readers.
In a sample of $350$350 people, it is found that only $1$1 has blood type B-negative.
Jimmy works on the top floor of a $50$50 storey building. The probability that the elevator will stop at another floor on its way up to his office is $p$p.
Jimmy has decided to test this probability by noting the outcome for every one of the $236$236 working days of the year, over five years. He records a $1$1 if the elevator does stop, and a $0$0 if it doesn't stop.
The average outcome for each year is shown in the table below.
$30$30 hamburger patties advertised as being $180$180 g are weighed and the results are tabulated.