![]() The confidence interval for the mean is (121.16, 132.01).Īs you might have observed, the interval widens as the level of confidence increases.Ĭalculate and interpret a confidence interval for a population mean, given a normal distribution with 1) a known population variance, 2) an unknown population variance, or 3) an unknown variance and a large sample size. We define a 100(1 – α)% confidence interval for a given parameter, say θ, by specifying two random variables, θ’ 1(X) and θ’ 2(X), such that P \\ In statistical terminology, 1- α is called the degree of confidence or certainty. This probability is represented by (1 – α), where α is the level of significance. When constructing confidence intervals, we must specify the probability that the interval contains the true value of the parameter of interest. Example: Let degrees of freedom be 20 and 0.05 (95 confidence). Enter the degrees of freedom, the direction of the inequality, and the probability (leave X blank). It differs from a point estimate which is a single, specific numerical value. Find a 95 confidence interval for the population mean. In general, you compute the 95 confidence interval for the mean with the following formula: Lower limit M - Z. Confidence interval (CI) refers to a range of values within which statisticians believe the actual value of a certain population parameter lies. This means that if we repeatedly compute the mean (M) from a sample, and create an interval ranging from M - 23.52 to M + 23.52, this interval will contain the population mean 95 of the time.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |