最美情侣中文字幕电影,在线麻豆精品传媒,在线网站高清黄,久久黄色视频

歡迎光臨散文網(wǎng) 會(huì)員登陸 & 注冊(cè)

[Calculus] Uniform Distribution

2021-11-29 09:17 作者:AoiSTZ23  | 我要投稿

By: Tao Steven Zheng (鄭濤)

【Problem】

Calculate the mean, median, and variance for the probability distribution function (PDF)

%20p(x)%20%3D%20%5Cfrac%7B1%7D%7Bb-a%7D%20

defined on the interval x%20%5Cin%20%5Ba%2Cb%5D and is zero elsewhere.

【Solution】

(1) Mean

The mean is the first moment of the PDF.

Var(X)%20%3D%20%5Cint_%7B-%5Cinfty%7D%5E%7B%5Cinfty%7D%20x%5E2%20%5Ccdot%20p(x)%20dx%20-%20%7B%5Cmu%7D%5E2

%5Cmu%20%3D%20%5Cint_%7Ba%7D%5E%7Bb%7D%20%5Cfrac%7Bx%7D%7Bb-a%7D%20dx

%20%5Cmu%20%3D%20%5Cfrac%7Bx%5E2%7D%7B2(b-a)%7D%5CBiggr%7C_a%5Eb

%5Cmu%20%3D%20%5Cfrac%7Bb%5E2%20-%20a%5E2%7D%7B2(b-a)%7D

%20%5Cmu%20%3D%20%5Cfrac%7Ba%2Bb%7D%7B2%7D


(2) Median

To calculate the median, one must obtain the cumulative distribution function (CDF).

P(x)%20%3D%20%5Cint_%7Ba%7D%5E%7Bx%7D%20%5Cfrac%7B1%7D%7Bb-a%7Ddt

P(x)%20%3D%20%5Cfrac%7Bx%7D%7Bb-a%7D%20%20%5CBiggr%7C_a%5Ex

P(x)%20%3D%20%5Cfrac%7Bx-a%7D%7Bb-a%7D

The median is located where the probability is 50%, so

P(x)%20%3D%200.5%20

%5Cfrac%7Bx-a%7D%7Bb-a%7D%20%3D%200.5

x%20%3D%20%5Cfrac%7Ba%2Bb%7D%7B2%7D%20


(3) Variance

The variance is calculated by subtracting the square of the mean from the second moment.

Var(X)%20%3D%20%5Cint_%7B-%5Cinfty%7D%5E%7B%5Cinfty%7D%20x%5E2%20%5Ccdot%20p(x)%20dx%20-%20%7B%5Cmu%7D%5E2

Var(X)%20%3D%20%5Cint_%7Ba%7D%5E%7Bb%7D%20%20%5Cfrac%7Bx%5E2%7D%7Bb-a%7D%20dx%20-%20%7B%5Cmu%7D%5E2

%20Var(X)%20%3D%20%5Cfrac%7Bx%5E3%7D%7B3(b-a)%7D%20%5CBiggr%7C_a%5Eb%20-%20%7B%5Cleft(%5Cfrac%7Ba%2Bb%7D%7B2%7D%5Cright)%7D%5E2

%20Var(X)%20%3D%20%5Cfrac%7Bb%5E3%20-%20a%5E3%7D%7B3(b-a)%7D%20-%20%5Cfrac%7Ba%5E2%2B2ab%2Bb%5E2%7D%7B4%7D

Since b%5E3%20-%20a%5E3%20%3D%20(b-a)(b%5E2%20%2B%20ab%20%2B%20a%5E2),

Var(X)%20%3D%20%5Cfrac%7Bb%5E2%20%2B%20ab%20%2B%20a%5E2%7D%7B3%7D%20-%20%5Cfrac%7Ba%5E2%20%2B%202ab%20%2B%20b%5E2%7D%7B4%7D

Var(X)%20%3D%20%5Cfrac%7Bb%5E2%20-%202ab%20%2B%20a%5E2%7D%7B12%7D%20

Var(X)%20%3D%20%5Cfrac%7B%7B(b-a)%7D%5E2%7D%7B12%7D

[Calculus] Uniform Distribution的評(píng)論 (共 條)

分享到微博請(qǐng)遵守國(guó)家法律
安乡县| 石首市| 团风县| 怀柔区| 扬中市| 海城市| 两当县| 西乡县| 铁岭市| 叶城县| 方山县| 葫芦岛市| 丰原市| 乐东| 曲水县| 淳安县| 临邑县| 大港区| 张北县| 宾阳县| 高台县| 斗六市| 松原市| 晋宁县| 沾益县| 广东省| 昌都县| 临桂县| 灌云县| 荔波县| 昆明市| 莒南县| 临安市| 伊宁县| 榕江县| 宜章县| 丰顺县| 婺源县| 堆龙德庆县| 韩城市| 台山市|