6.2] What is the T-distribution?

When do we use the T-Distribution vs the Z-Distribution:

What is a critical value of a distribution?

Why do we use the t-distribution instead of the normal distribution?

What are Degrees of freedom? How do we calculate degrees of freedom from a sample of N=30, DF=30-1=29.

How do we calculate the standard deviation in a T-distribution, how is it different from a normal distribution?

x=xn,s=x-xn-1

How do we use this in a T-Distribution? What’s the difference between a normal distribution vs. a T-Distribution.

What are the conditions for to use the T-Distribution or a normal distribution?

Calculate confidence intervals: for the two groups: