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

ההשפעה של שינוי השיטה, המדגם או האנליטיקאי על תוצאות הניתוח נלמדת על ידי שינוי אחד בלבד בזוג ניסויים.
מבחן t משווה את המובהקות הסטטיסטית של ממוצע אחד עם ערך ממוצע של ממוצע אחר או עם ערך ידוע.
במבחן t, נתונים לא מזווגים הם שתי קבוצות נתונים בלתי תלויות מאותו מקור. נתונים משויכים הם שתי קבוצות של נתונים קשורים, לדוגמה, שתי קבוצות משתי שיטות שונות בסדרה של דגימות.
סטטיסטיקת הבדיקה נגזרת מהרווח בר-סמך שנבחר עבור ערך ידוע. בהשוואה לערך הסטטיסטי של המבחן עבור דרגת חופש נתונה ברמת מובהקות נבחרת, אם הערך הראשון נמצא בטווח של האחרון, השערת האפס מתקבלת.
מבחן חד-זנבי מחפש רק עלייה או רק ירידה, בעוד מבחן דו-זנבי מחפש שינוי בשני הכיוונים.

השוואת תוצאות ניסוי: מבחן סטודנט   t

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מבחן ה-t הוא שיטה סטטיסטית המשמשת להשוואת ממוצע המדגם עם ממוצע אוכלוסיה או השוואת שני אמצעים משני מערכי נתונים. סטטיסטיקת הבדיקה מחושבת מתוך סטיית התקן, הממוצע ומספר המדידות במערך הנתונים ברווח סמך נבחר ולאחר מכן בהשוואה לטבלה של ערכים קריטיים ברמת ביטחון זו. אם נתון המבחן קטן מהערך הקריטי, השערת האפס מתקבלת. במקרה זה, אנו קובעים שההבדל בין האמצעים אינו מובהק סטטיסטית ולכן נובע משגיאות בלתי מוגדרות (אקראיות). אם נתון הבדיקה גבוה מהערך הקריטי, השערת האפס נדחית. במקרה זה, אנו קובעים שההבדל בין האמצעים הוא מובהק סטטיסטית ואינו יכול להיות מוסבר על ידי טעויות אקראיות. ההבדל נובע משגיאות בשיטה, בדגימה, באנליטיקאים עצמם או מהבדלים פנומנולוגיים אמיתיים. בסטטיסטיקה, ניתן לבצע בדיקות t על נתונים לא מזווגים כמו גם נתונים מזווגים. נתונים לא מותאמים הם שתי קבוצות של מדידות משוכפלות מאותו מקור; נתונים זוגיים מתייחסים לנתונים שנלקחו על אותן דגימות או נושאים משתי שיטות שונות או בשתי נקודות זמן שונות להשוואה. כאשר משתמשים רק בצד אחד של עקומת התפלגות נורמלית במבחן t, זוהי מבחן חד-זנבי. אם משתמשים בשני הצדדים של ההתפלגות במבחן t, המבחן הוא דו-זנבי.
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השוואת תוצאות ניסוי: מבחן סטודנט   T

ההשפעה של שינוי השיטה, המדגם או האנליטיקאי על תוצאות הניתוח נלמדת על ידי שינוי אחד בלבד בזוג ניסויים.
ה...

Education

JoVE Core

Analytical Chemistry

כימיה אנליטית

Unit 1

יחידה 1

Chemical Applications of Statistical Analyses

יישומים כימיים של ניתוחים סטטיסטיים

chemical-applications-of-statistical-analyses

KEY TERMS AND CONCEPTS

מונחי מפתח ומושגים

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

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Student's t-Test for Significance Checks

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