Name: student's t-test for significance checks
Uploaded: 2024-04-04T10:51:12.000Z
Duration: 1 min 9 s
Channel: JoVE

K12 Standards

Texas Essential Knowledge and Skills

High School

Chemistry

CHEM.2

CHEM.2.C

comparing-experimental-results-student-s-t-test

Comparing Experimental Results: Student's t-Test

تتم دراسة تأثير تغيير الطريقة أو العينة أو المحلل على نتائج التحليل عن طريق تغيير واحدة فقط في زوج من التجربة.
يقارن اختبار t الدلالة الإحصائية لوسيط بمتوسط قيمة أخرى أو بقيمة معروفة.
في اختبار t ، البيانات غير المقترنة عبارة عن مجموعتين مستقلتين من البيانات من نفس المصدر. البيانات المقترنة عبارة عن مجموعتين من البيانات ذات الصلة ، على سبيل المثال ، مجموعتان من طريقتين مختلفتين في سلسلة من العينات.
يتم اشتقاق إحصائية الاختبار من فاصل الثقة المحدد لقيمة معروفة. بالمقارنة مع القيمة الإحصائية للاختبار المجدولة لدرجة معينة من الحرية عند مستوى الدلالة المختار ، إذا كانت القيمة الأولى ضمن نطاق الأخير ، يتم قبول الفرضية الصفرية.
يبحث الاختبار أحادي الذيل عن زيادة فقط أو نقصان فقط ، بينما يبحث الاختبار ذو الذيل عن تغيير في أي من الاتجاهين.

مقارنة النتائج التجريبية: اختبار t للطالب

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اختبار t هو طريقة إحصائية تستخدم لمقارنة متوسط ​​العينة مع متوسط ​​المجتمع أو مقارنة وسطين من مجموعتين من البيانات. يتم حساب إحصائية الاختبار من الانحراف المعياري والمتوسط ​​وعدد القياسات في مجموعة البيانات عند فاصل ثقة محدد ثم تتم مقارنتها بجدول القيم الحرجة عند مستوى الثقة هذا. إذا كانت إحصائية الاختبار أصغر من القيمة الحرجة، يتم قبول الفرضية الصفرية. في هذه الحالة، نذكر أن الفرق بين المتوسطات ليس ذو دلالة إحصائية وبالتالي يأتي من أخطاء غير محددة (عشوائية). إذا كانت إحصائية الاختبار أعلى من القيمة الحرجة، يتم رفض الفرضية الصفرية. وفي هذه الحالة نذكر أن الفرق بين المتوسطين ذو دلالة إحصائية ولا يمكن تفسيره بأخطاء عشوائية. ويأتي الاختلاف من أخطاء في الطريقة، أو أخذ العينات، أو المحللين أنفسهم، أو الاختلافات الظاهرية الحقيقية. في الإحصاء، يمكن إجراء اختبارات t على البيانات غير المقترنة وكذلك المقترنة. البيانات غير المقترنة عبارة عن مجموعتين من القياسات المكررة من نفس المصدر؛ تشير البيانات المقترنة إلى البيانات المأخوذة من نفس العينات أو الموضوعات من طريقتين مختلفتين أو في نقطتين زمنيتين مختلفتين للمقارنة. عندما يتم استخدام جانب واحد فقط من منحنى التوزيع الطبيعي في اختبار t، فهو اختبار ذو ذيل واحد. إذا تم استخدام كلا جانبي التوزيع في اختبار t، يكون الاختبار ثنائي الذيل.
</div>

مقارنة النتائج التجريبية: اختبار T للطالب

تتم دراسة تأثير تغيير الطريقة أو العينة أو المحلل على نتائج التحليل عن طريق تغيير واحدة فقط في زوج من التجربة.
ال...

Education

JoVE Core

Analytical Chemistry

الكيمياء التحليلية

Unit 1

الوحدة الأولى

Chemical Applications of Statistical Analyses

التطبيقات الكيميائية للتحليلات الإحصائية

chemical-applications-of-statistical-analyses

KEY TERMS AND CONCEPTS

المصطلحات والمفاهيم الأساسية

student's t-test for significance checks

Student's t-test is a statistical tool for checking whether two means are different in a meaningful way. It can compare a sample mean with a population mean, or it can compare the means from two data sets. The test uses the mean, standard deviation, and number of measurements, along with a chosen confidence interval.

The test statistic is then compared with a table of critical values at that confidence level. If the test statistic is smaller than the critical value, the null hypothesis is accepted. That means the difference between the means is not statistically significant and is likely due to random, indeterminate errors.

If the test statistic is higher than the critical value, the null hypothesis is rejected. In that case, the difference is statistically significant and cannot be explained by random errors alone. The cause may come from the method, the sampling, the analyst, or a real difference in the phenomenon being studied.

Student's t-tests can be used with unpaired or paired data. Unpaired data are two sets of replicate measurements from the same source. Paired data are measurements taken on the same samples or subjects with two methods, or at two different time points, for comparison. The test can also be one-tailed, when only one side of the normal distribution curve is used, or two-tailed, when both sides are used.

Student's t-Test for Significance Checks

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Student's t-test is a statistical tool for checking whether two means are different in a meaningful way. It can compare a sample mean with a population mean, or it can compare the means from two data sets. The test uses the mean, standard deviation, and number of measurements, along with a chosen confidence interval. The test statistic is then compared with a table of critical values at that confidence level. If the test statistic is smaller than the critical value, the null hypothesis is...

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Learn how Student's t-test compares means, uses critical values, and helps decide whether a result is statistically significant in high school science.

Student's t-Test for Significance Checks | JoVE K12

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Student's t-Test for Significance Checks

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