Estimate the chance that the sample proportion was more than 45% using a normal approximation.

A random sample of 100 inmates at a maximum-security prison shows that exactly 10 of the respondents had been the victims of violent crime during their incarceration.    Estimate the proportion of victims for the population as a whole assuming a 10% tolerance for error and interpret the result.  Prison guards have suggested that 20% of inmates are victims of violent crime. Is the evidence consistent or inconsistent with this suggestion. Briefly explain.

A university dean wishes to estimate the average number of hours that freshmen study each week. The standard deviation from previous study is 6 hours. How large a sample must be selected if the dean wants his estimate to be within 0.3 from the true mean with 90% confidence?

You are conducting a study to estimate the mean height of students in a university. The university has 10,000 students. If you want to achieve a margin of error of no more than 2 inches with 95% confidence, what sample size should you select?

In a random sample of 250 high school students, it was found that 85.2% (213) of them later graduated. Find the 95% and 98% confidence interval for the true proportion of all high school students who graduate. Compare the two proportions.

In the US, 45.1% of all people have type O blood, 39.6% have type A blood, 10.9% have type B blood and 4.4% have type AB blood. A researcher wants to see if the distribution of blood type is different for millionaires. The table below shows the results of a random sample of 614 millionaires. What can be concluded at the significant level of a = 0.05. For this study, we should use Chi-Square test for Goodness of Fit Your friend Caroline helped you with the null and alternative hypotheses... Ho : The distributions of blood types are the same between the general population and the millionaires. Ha: The distributions of blood types are NOT the same between the general population and the millionaires. You drew 614 samples, and the observed frequencies are recorded below. Please complete the table (round answers to at least 4 decimal places). Blood Type 0 A B AB Observed Count 274 230 57 53 Expected Count Click Download CSV to download csv file of data or copy/paste the data into Excel.…

Suppose you want to find out how many people support Policy X. A standard polling approach is to just ask N many people whether or not they support Policy X, and take the fraction of people who say yes as an estimate of the probability that any one person supports the policy. Suppose that the probability someone supports the policy is p, which you do not know. Let pn be the number of people polled who supported the policy, divided by the total number of people polled N.

Nearly one-half of Americans ages 25 to 29 are unmarried. How large a sample is necessary to estimate the true proportion of unmarried Americans in this age group within 2 percentage points with 95% confidence?

In a recent survey of 100 users of a certain social media website, 29 said they thought website staff did a good job of punishing inappropriate users. Find the standard error for the sample proportion of website users who think the website staff does a good job of punishing inappropriate users.

Find the Margin of Error, if we are asked for 90% confidence interval where the mean is 52.3, the standard deviation is 2.15 and the sample size is 136.