Confidence Interval Calculator (1 or 2 means) Calculate the confidence interval of a sample set. . In this specific case, the objective is to construct a confidence interval (CI) for the difference between two population means (. Enter the sample number, the sample mean, and standard deviation to calculate the confidence interval. or [19.713 – 21.487] Calculating confidence intervals: Calculating a confidence interval involves determining the sample mean, X̄, and the population standard deviation, σ, if possible. . To find a confidence interval for a difference between two population proportions, simply fill in the boxes below and then click the “Calculate” button. Confidence interval = ( x1 – x2) +/- t*√ ( (s p2 /n 1) + (s p2 /n 2 )) where: x1, x2: sample 1 mean, sample 2 mean. Point Estimate Calculator. −μ2. ), or the relative difference between two proportions or two means. μ 1 − μ 2. n2 (sample 2 size) ), in the case that the population standard deviation are not known, in which case the expression for the confidence interval is: C I = ( X ˉ 1 − X ˉ 2 − t c × s 1 2 n 1 + s 2 2 n 2, X ˉ 1 − X ˉ 2 + t c s 1 2 n 1 + s 2 2 n 2) This confidence interval calculator allows you to perform a post-hoc statistical evaluation of a set of data when the outcome of interest is the absolute difference of two proportions (binomial data, e.g. t: the t-critical value based on the confidence level. t = t statistic determined by confidence level. The formula for estimation is: μ 1 - μ 2 = ( M1 - M2) ± ts(M1 - M2) where: M1 & M2 = sample means. \mu_1 - \mu_2 μ1. n 1, n 2: sample 1 size, sample 2 size. height, weight, speed, time, revenue, etc. −μ2. T Statistic Calculator. You can also calculate a confidence interval for the mean of just a single group. \mu_1 - \mu_2 μ1. It can also be written as simply the range of values. μ 1 − μ 2. s p2: pooled variance. ), the following expression for the confidence interval is used: C I = ( X ˉ 1 − X ˉ 2 − z c σ 1 2 n 1 + σ 2 2 n 2, X ˉ 1 − X ˉ 2 + z c σ 1 2 n 1 + σ 2 2 n 2) CI = \left (\bar X_1 - \bar X_2 - z_c \sqrt {\frac {\sigma_1^2} {n_1}+\frac … or. Z-Score Calculator. It uses the Z-distribution (normal dist… conversion rate or event rate) or the absolute difference of two means (continuous data, e.g. For example, the following are all equivalent confidence intervals: 20.6 ±0.887. . . 20.6 ±4.3%. This simple confidence interval calculator uses a t statistic and two sample means ( M1 and M2) to generate an interval estimate of the difference between two population means (μ 1 and μ 2 ). In this specific case, we are interested in constructing a confidence interval for the difference between two population means (. To find a confidence interval for a difference between two means, simply fill in the boxes below and then click the “Calculate” button.