stats choose two

Please choose two of the following topics as your main topic

(1) When do we use Chi-Square distirbution? Please give one example.

(2) You are asked to leverage linear regression to find some predicted values. Based on the given values of  -1, 1, 2, 3 and 5 and the corresponding y values, you get the linear regression equation as y ˆ=3x+1.Would you feel comfortable to find the predicted value of y for x = 100 using this equation? Why or why not?

(3) When computing the linear correlation coefficient between two variables, Mimi found the test statistic for the linear correlation coefficient was between the two critical values. Hence, she concluded that " There is not sufficient evidence to support these two variables are correlated." Did she have a correct conclusion? Why or why not?