Question

What Is Confidence Interval, and how can it be used? Could you please give me a few examples and thanks so much.

Answer 1

Solution:

A confidence interval is an estimate of an interval in statistics that may contain a population parameter. The unknown population parameter is found through a sample parameter calculated from the sampled data. For example, the population mean μ is found using the sample mean x̅.

The interval is generally defined by its lower and upper bounds. The confidence interval is expressed as a percentage (the most frequently quoted percentages are 90%, 95%, and 99%). The percentage reflects the confidence level.

The confidence interval tells you how confident you are in your results. With any survey or experiment, you’re never 100% sure that your results could be repeated. If you’re 95% sure, or 98% sure, that’s usually considered good enough in statistics. That percentage of sureness is the confidence interval.

Example :

Say you wanted to determine the average age of victims of robberies in Mumbai last year. Now, while there is a true answer, say 30 years old, the best you can do is find an interval that the true answer probably lies in, say, 20-40 years old.The confidence interval is the sample mean or proportion plus or minus the margin of error (ME), which is the value used to calculate the upper limit and lower limit of the sample statistic. In this case, the upper limit is 40, and the lower limit is 20.Before calculating the CI from a sample mean or proportion, choose either a 90%, 95%, or 99% confidence level (CL). This is the amount of uncertainty in the sampling method, meaning each time the same sampling method is used, the true population value would be represented in 90%, 95%, or 99% of all the sample estimated CIs. That also means that 10%, or 5%, or 1% would not contain the true population score.