## What is T in null hypothesis?

A t-test is a statistical test that compares the means of two samples. It is used in hypothesis testing, with a null hypothesis that the difference in group means is zero and an alternate hypothesis that the difference in group means is different from zero.

## Can you use SQL for statistics?

If you wonder whether you can perform statistical analysis in SQL, the answer is ‘yes’.

What does the t-value represent?

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.

### Why is SQL used in data science?

A Data Scientist needs SQL in order to handle structured data. This structured data is stored in relational databases. Therefore, in order to query these databases, a data scientist must have a sound knowledge of SQL.

### Why is SQL used in data analytics?

Though SQL is commonly used by engineers in software development, it’s also popular with data analysts for a few reasons: It’s semantically easy to understand and learn. Because it can be used to access large amounts of data directly where it’s stored, analysts don’t have to copy data into other applications.

How do you write the null and alternative hypothesis for t-test?

The null is not rejected unless the hypothesis test shows otherwise. The null statement must always contain some form of equality (=, ≤ or ≥) Always write the alternative hypothesis, typically denoted with Ha or H1, using less than, greater than, or not equals symbols, i.e., (≠, >, or <).

#### How do you reject the null hypothesis in t-test?

If the absolute value of the t-value is greater than the critical value, you reject the null hypothesis. If the absolute value of the t-value is less than the critical value, you fail to reject the null hypothesis.

#### What is the null hypothesis of a two-sample t-test?

The default null hypothesis for a 2-sample t-test is that the two groups are equal. You can see in the equation that when the two groups are equal, the difference (and the entire ratio) also equals zero.