independent sample t test

Question

A 95% confidence interval for the difference of means is calculated to be -1.23 to -0.33. What conclusion can be made? Select all that are true.

Question 9 options:

The two group means are equal.


The two group means are significantly different.


The two group means are not significantly different.


No conclusion can be made from the confidence interval.

Answer 1

The answer is:

 

The two group means are significantly different. 

 

How do we know this?

 

What would be the difference if the means were the same. It would be 0.

 

Does the 95% confidence contain 0, no because the interval is from -1.23 to -.33. Only if one sign is negative and the other is positive, does that interval contain zero.

 

Therefore the differences in the mean are significantly different from 0.

 

Hope this helps.