Could you help giving me explanations on this problems ?

Problem 1:

Box A contains 10 chocolate chip cookies. Box B contains 5 chocolate chip cookies, 3 ginger bread cookies, and 2 oatmeal cookies. You randomly chose one cookie from all 20 cookies and it turned out to be a chocolate chip cookie. What is the probability that it is from box A? (ey A : Which of the following are true statements? Select all that apply: Choose as many as you like u 95% confidence interval is a random interval that contains the true parameter 95% of the time The true parameter is a random value that has 95% chance of falling in the 95% confidence interval I perform a linear regression and get a 95% confidence interval from 0.4 to 0.5. There is a 95% probability that the true parameter is between 0.4 and 0.5. n The true parameter (unknown to me) is 0.5. IfI sample data and construct a 95% confidence interval, the interval will contain 0.5 95% of the time