Basic Statistics Help

[ilovesleep]

Hi all,
I’m currently taking a statistics class and very much regretting it as I find in class I understand the concepts initially yet can never seem to apply them or get confused and thus struggle with the basics.
I would very much appreciate help with this section of homework questions.

For all 4 questions I would assume graph b will be significantly different as the variations is mean is large and there is no overlap between the error bars at all?
I'm not sure what difference it makes in part c and d to change from two standard errors to one and then to standard deviation ( I thought standard error was just another way or representing standard deviation for the whole population).

 

Thank you!

Edited April 14, 2019 by ilovesleep
new info