ALC Exam STA4211 Questions with 100% Correct Answers | Verified & Updated 2024

ALC Exam STA4211 Questions with 100% Correct Answers | Verified & Updated 2024 Parameter vs statistic - Answer ️️ -A parameter is a measure that describes the entire population, whereas a statistic describes a sample of the population. Testing for sample means vs proportions - Answer ️️ - sampling distribution - Answer ️️ -probability distribution of a given statistic based on a random sample unbiased estimator - Answer ️️ -An unbiased estimator is an accurate statistic that's used to approximate a population parameter. "Accurate" in this sense means that it's neither an overestimate nor an underestimate. If an overestimate or underestimate does happen, the mean of the difference is called a "bias." bias( thetahat) = E(thetahat) - (thetahat) margin of error - Answer ️️ -In a confidence interval, the range of values above and below the sample statistic is called the margin of error. standard error - Answer ️️ -The standard error is an estimate of the standard deviation of a statistic. The standard error is computed from known sample statistics. interpreting a confidence interval - Answer ️️ -"We are 95% confident that the mean time it takes all workers in this city to get to work is between 18.3 and 23.7 minutes." increase in sample size or decrease in confidence level - Answer ️️ -more precise or narrow confidence interval type 1 and type 2 error - Answer ️️ -Type 1- rejecting the null when it is actually true Type 2- fail to reject null when it is actually false (dangerous) p-value - Answer ️️ -All hypothesis tests ultimately use a p-value to weigh the strength of the evidence. The p-value is a number between 0 and 1 and interpreted in the following way: A small p-value (typically ≤ 0.05) indicates strong evidence against the null hypothesis, so you reject the null hypothesis. How do we graphically check whether a data set is a drawn from a normal distribution? - Answer ️️ -•bell shape