A t-test is a type of inferential statistic used to determine if there is a significant difference between the means of two groups, which may be related in certain features. The t-test is one of many tests used for the purpose of hypothesis testing in statistics. Calculating a t-test requires three key data values.

Also, How do you find the standardized test statistic?

Standardized Test Statistic Formula

The general formula is: Standardized test statistic: (statistic-parameter)/(standard deviation of the statistic). The formula by itself doesn’t mean much, unless you also know the three major forms of the equation for z-scores and t-scores.

Hereof, What are the 3 types of t tests?


There are three types of t-tests we can perform based on the data at hand:

  • One sample t-test.
  • Independent two-sample t-test.
  • Paired sample t-test.

Also to know What does the t statistic tell you? The t-value measures the size of the difference relative to the variation in your sample data. Put another way, T is simply the calculated difference represented in units of standard error. The greater the magnitude of T, the greater the evidence against the null hypothesis.

What is p-value in t test?

A p-value is the probability that the results from your sample data occurred by chance. P-values are from 0% to 100%. They are usually written as a decimal. For example, a p value of 5% is 0.05. Low p-values are good; They indicate your data did not occur by chance.

21 Related Questions Answers Found

How do you find P value from standardized test statistic?

If your test statistic is positive, first find the probability that Z is greater than your test statistic (look up your test statistic on the Z-table, find its corresponding probability, and subtract it from one). Then double this result to get the p-value.

What is the test statistic value?

A test statistic is a standardized value that is calculated from sample data during a hypothesis test. … A t-value of 0 indicates that the sample results exactly equal the null hypothesis. As the difference between the sample data and the null hypothesis increases, the absolute value of the t-value increases.

What is the formula for at test?

T-test formula

In this formula, t is the t-value, x1 and x2 are the means of the two groups being compared, s2 is the pooled standard error of the two groups, and n1 and n2 are the number of observations in each of the groups.

How do you calculate the T value?

Calculate your T-Value by taking the difference between the mean and population mean and dividing it over the standard deviation divided by the degrees of freedom square root.

What does an Anova test tell you?

Like the t-test, ANOVA helps you find out whether the differences between groups of data are statistically significant. It works by analyzing the levels of variance within the groups through samples taken from each of them.

Which t-test should I use?

If you are studying one group, use a paired t-test to compare the group mean over time or after an intervention, or use a one-sample t-test to compare the group mean to a standard value. If you are studying two groups, use a two-sample t-test. If you want to know only whether a difference exists, use a two-tailed test.

How do you interpret t-test results?

The basic format for reporting the result of a t-test is the same in each case (the color red means you substitute in the appropriate value from your study): t(degress of freedom) = the t statistic, p = p value. It’s the context you provide when reporting the result that tells the reader which type of t-test was used.

Is test statistic the same as p-value?

The test statistic is used to calculate the p-value. A test statistic measures the degree of agreement between a sample of data and the null hypothesis. … This Z-value corresponds to a p-value of 0.0124. Because this p-value is less than α, you declare statistical significance and reject the null hypothesis.

Is T score the same as test statistic?

What is the T Score Formula? A t score is one form of a standardized test statistic (the other you’ll come across in elementary statistics is the z-score). The t score formula enables you to take an individual score and transform it into a standardized form>one which helps you to compare scores.

What is p-value formula?

The p-value is calculated using the sampling distribution of the test statistic under the null hypothesis, the sample data, and the type of test being done (lower-tailed test, upper-tailed test, or two-sided test). … an upper-tailed test is specified by: p-value = P(TS ts | H 0 is true) = 1 – cdf(ts)

How do I calculate p-value?

If your test statistic is positive, first find the probability that Z is greater than your test statistic (look up your test statistic on the Z-table, find its corresponding probability, and subtract it from one). Then double this result to get the p-value.

What does p-value of 1 mean?

Popular Answers (1)

When the data is perfectly described by the resticted model, the probability to get data that is less well described is 1. For instance, if the sample means in two groups are identical, the p-values of a t-test is 1.

What is p-value in hypothesis testing?

In statistics, the p-value is the probability of obtaining results at least as extreme as the observed results of a statistical hypothesis test, assuming that the null hypothesis is correct. … A smaller p-value means that there is stronger evidence in favor of the alternative hypothesis.

How do you find p-value on calculator?

We can find this value using the Normalcdf feature of the calculator found by pressing [2nd] [VARS] as noted above. The calculator will expect the following: Normalcdf(lowerbound, upperbound). Try typing in: Normalcdf(-10, -2.01) , after pressing [ENTER] you should get the same p-value as above.

What is the test statistic for Anova?

The test statistic is the F statistic for ANOVA, F=MSB/MSE. Step 3. Set up decision rule.

What is the p-value in at test?

A p-value is a measure of the probability that an observed difference could have occurred just by random chance. The lower the p-value, the greater the statistical significance of the observed difference. P-value can be used as an alternative to or in addition to pre-selected confidence levels for hypothesis testing.

What is the sample size for t test?

The parametric test called t-test is useful for testing those samples whose size is less than 30. The reason behind this is that if the size of the sample is more than 30, then the distribution of the t-test and the normal distribution will not be distinguishable.

What is p-value in statistics?

In statistics, the p-value is the probability of obtaining results at least as extreme as the observed results of a statistical hypothesis test, assuming that the null hypothesis is correct. … A smaller p-value means that there is stronger evidence in favor of the alternative hypothesis.

How do you solve for t test?


Paired Samples T Test By hand

  1. Example question: Calculate a paired t test by hand for the following data:
  2. Step 1: Subtract each Y score from each X score.
  3. Step 2: Add up all of the values from Step 1. …
  4. Step 3: Square the differences from Step 1.
  5. Step 4: Add up all of the squared differences from Step 3.