El intervalo de confianza del 95% para la diferencia real entre el contenido de carne de res de las dos marcas de fabricación de hamburguesas está entre 0, 006g y 0, 59g.
◘Desarrollo : Datos.
Marca 1 Marca 2n1 = 124 n2 = 180X(promedio)1 = 24, 6 X(promedio)2 = 24, 3σ1 = 1, 4 σ2 = 1, 1<img src="https://tex.z-dn.net/?f=%5Ctriangle%5Coverline%7BX%7D%3D%20%5Coverline%7BX%7D1-%5Coverline%7BX%7D2" /><img src="https://tex.z-dn.net/?f=%5Ctriangle%5Coverline%7BX%7D%3D%2024%2C6-24%2C3" /><img src="https://tex.z-dn.net/?f=%5Ctriangle%5Coverline%7BX%7D%3D%200%2C3" />Desviación de <img src="https://tex.z-dn.net/?f=%5Csigma_%7B%5Ctriangle%5Coverline%7Bx%7D%7D" /><img src="https://tex.z-dn.net/?f=%5Csqrt%7B%5Cfrac%7B%28%5Csigma_%7B1%7D%29%5E%7B2%7D%7D%7Bn1%7D%2B%5Cfrac%7B%28%5Csigma%20_%7B2%7D%29%5E%7B2%7D%7D%7Bn2%7D%20%7D" /><img src="https://tex.z-dn.net/?f=%5Csqrt%7B%5Cfrac%7B%281%2C4%29%5E%7B2%7D%7D%7B124%7D%2B%5Cfrac%7B%281%2C1%29%5E%7B2%7D%7D%7B180%7D%20%7D%3D0%2C15" /><img src="https://tex.z-dn.net/?f=%5Csigma_%7B%5Ctriangle%5Coverline%7Bx%7D%3D0%2C15%7D" />95% : 1 - ∝ = 0, 95 → ∝ = 1 - 0, 95 → ∝ = 0, 05∝ / 2 = 0, 05 / 2 → 0, 025Z(1 - ∝ / 2) = Z(0, 975) = 1, 956<img src="https://tex.z-dn.net/?f=P%3D%5Ctriangle%5Coverline%7BX%7D-Z_%7B1-%5Cfrac%7B%5Calpha%7D%7B2%7D%7D%2A%5Csqrt%7B%5Cfrac%7B%28%5Csigma_%7B1%7D%29%5E%7B2%7D%7D%7Bn1%7D%2B%5Cfrac%7B%28%5Csigma%20_%7B2%7D%29%5E%7B2%7D%7D%7Bn2%7D%7D%3C%5Ctriangle%5Cmu%3C%5Ctriangle%5Coverline%7BX%7D%2BZ_%7B1-%5Cfrac%7B%5Calpha%7D%7B2%7D%7D%2A%5Csqrt%7B%5Cfrac%7B%28%5Csigma_%7B1%7D%29%5E%7B2%7D%7D%7Bn1%7D%2B%5Cfrac%7B%28%5Csigma%20_%7B2%7D%29%5E%7B2%7D%7D%7Bn2%7D%7D" />P = 0, 3 - 1, 956 * 0, 15∠<img src="https://tex.z-dn.net/?f=%5Ctriangle%5Cmu" />∠0, 3 + 1, 956 * 0, 150, 006∠<img src="https://tex.z-dn.net/?f=%5Ctriangle%5Cmu" />∠0, 59.