Bài 3: Các số đặc trưng đo mức độ phân tán cho mẫu số liệu không ghép nhóm
<span data-v-a7c68f28="">Hướng dẫn Giải Luyện tập - Vận dụng 2 (Trang 39 SGK Toán 10, Bộ Cánh diều, Tập 2)</span>
<p><strong>Luyện tập - Vận dụng 2 (Trang 39 SGK To&aacute;n 10, Bộ C&aacute;nh diều, Tập 2)</strong></p> <p>Mẫu số liệu về số lượng &aacute;o b&aacute;n ra lần lượt từ th&aacute;ng 1 đến th&aacute;ng 12 của một doanh nghiệp l&agrave;:</p> <p style="text-align: left;" align="center">430 560 450 550 760 430</p> <p style="text-align: left;" align="center">525 410 635 450 800 900</p> <p>T&iacute;nh độ lệch chuẩn của mẫu số liệu đ&oacute;</p> <p><em><span style="text-decoration: underline;"><strong>Hướng dẫn giải</strong></span></em></p> <p>+) Ta c&oacute; b&agrave;ng tần số:</p> <p><img class="wscnph" style="max-width: 100%;" src="https://static.colearn.vn:8413/v1.0/upload/library/13112022/61-Vv4fb6.png" width="800" height="78" /></p> <p>+) Từ bảng tần số ta c&oacute; số lượng &aacute;o trung b&igrave;nh b&aacute;n ra trong 1 th&aacute;ng l&agrave;:<br /><math xmlns="http://www.w3.org/1998/Math/MathML"><mover><mi>x</mi><mo>&macr;</mo></mover><mo>&nbsp;</mo><mo>=</mo><mo>&nbsp;</mo><mn>602</mn></math> (chiếc &aacute;o)</p> <p>+) Phương sai của mẫu số liệu l&agrave;:</p> <p><math xmlns="http://www.w3.org/1998/Math/MathML"><msup><mi>s</mi><mn>2</mn></msup><mo>&nbsp;</mo><mo>=</mo><mo>&nbsp;</mo><mfrac><mn>1</mn><mn>12</mn></mfrac></math>[(430 &minus; 575)<sup>2</sup>&nbsp;+ (560 &minus; 575)<sup>2</sup>&nbsp;+ (450 &minus; 575)<sup>2</sup>&nbsp;+ (550 &minus; 575)<sup>2</sup>&nbsp;+ (760 &ndash; 575)<sup>2</sup>&nbsp;+ (430 &minus; 575)<sup>2</sup>&nbsp;</p> <p>+ (525 &ndash; 575)<sup>2</sup>&nbsp;+ (410 &minus; 575)<sup>2</sup>&nbsp;+ (635 &minus; 575)<sup>2</sup>&nbsp;+ (450 &minus; 575)<sup>2</sup>&nbsp;+ (800 &minus; 575)<sup>2</sup>&nbsp;+ (900 &ndash; 575)<sup>2</sup>] &asymp; 24829,17.</p> <p>Vậy độ lệch chuẩn của mẫu số liệu tr&ecirc;n l&agrave;:&nbsp;<math xmlns="http://www.w3.org/1998/Math/MathML"><mi>s</mi><mo>&nbsp;</mo><mo>=</mo><msqrt><msup><mi>s</mi><mn>2</mn></msup></msqrt><mo>&nbsp;</mo><mo>=</mo><mo>&nbsp;</mo><msqrt><mn>24829</mn><mo>,</mo><mn>17</mn></msqrt><mo>&nbsp;</mo><mo>&asymp;</mo><mo>&nbsp;</mo><mn>157</mn><mo>,</mo><mn>57</mn></math></p> <p><span id="MathJax-Element-5-Frame" class="mjx-chtml MathJax_CHTML" style="margin: 0px; padding: 1px 0px; display: inline-block; line-height: 0; text-indent: 0px; text-align: left; text-transform: none; font-style: normal; font-weight: normal; font-size: 16.94px; letter-spacing: normal; overflow-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; position: relative;" tabindex="0" role="presentation" data-mathml="&lt;math xmlns=&quot;http://www.w3.org/1998/Math/MathML&quot;&gt;&lt;mtable columnalign=&quot;left&quot; rowspacing=&quot;4pt&quot; 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