4. Statistical Inference
Interval Estimation — Quiz
Test your understanding of interval estimation with 5 practice questions.
Practice Questions
Question 1
A researcher wants to estimate the average weight of a certain species of fish. A sample of $40$ fish is taken, and the sample mean weight is $1.5$ kg with a sample standard deviation of $0.2$ kg. What is the $95\%$ confidence interval for the population mean weight?
Question 2
A political pollster wants to estimate the proportion of voters who support a particular candidate. In a random sample of $200$ voters, $110$ indicate support for the candidate. What is the $95\%$ confidence interval for the true proportion of voters who support the candidate?
Question 3
A quality control engineer wants to estimate the average weight of a certain component. A random sample of $30$ components has a mean weight of $15.2$ grams and a standard deviation of $0.5$ grams. What is the $99\%$ confidence interval for the true mean weight of the components?
Question 4
A researcher is studying the variability of reaction times to a stimulus. A sample of $25$ individuals yields a sample variance of $1.44$ seconds$^2$. What is the $90\%$ confidence interval for the true population variance of reaction times?
Question 5
A company claims that the average lifespan of its new light bulbs is $1000$ hours. A consumer group tests $49$ light bulbs and finds a sample mean lifespan of $980$ hours with a population standard deviation of $60$ hours. What is the $95\%$ confidence interval for the true average lifespan of these light bulbs?