Question

there is a discussion about how confidence intervals can be used to infer facts from your sample to the population. Select a variable you are likely to work with in your career, then using the video and the text in this course, answer the following questions:

1. Describe the variable and how it might be used in your career (the example from the video is battery life).

2. Explain why you would need to use a sample to infer something about the population.

3. In your own words, explain why you believe that a confidence interval will accurately predict the mean of the population from which the sample was drawn?

4. What would happen if the confidence interval for your chosen variable did not include the value of the population mean?

5. What changes to sample would make you more certain that the confidence interval contained the value of the population mean?

Answer 1

1. We have a taken the data of survival time of cancer patients and I should to analysis to avarage time to survival of cancer patients with certain limit based on sample.

2. Always, study on whole population is better than study on sample. If we have time, energy and structure sampling frame, we should go for study of whole population but sometimes this is not happended, then we go for sample

3. The particular value chosen as most likely for a population parameter is called the point estimate. Because of sampling error, we know the point estimate probably is not identical to the population parameter. Because the point estimate is unlikely to be exactly correct, we usually specify a range of valuesin which the population parameter is likely to be called confidence interval. We consider confidence interval also as a measure of the sample and research quality. So, it can accurately predict the mean of the population from which the sample was drawn.

4. Some times confidence interval for your chosen variable did not include the value of the population mean, then we can redefine the sample which is correctly verify the population and then the confidence interval is done or if we may increase the sample size or mau=y be leavel of signficance.