Suppose we have a stream of tuples with the schema grades(university, courseid, studentid, grade) assume universities are unique, but a courseid is unique only within a university (i. e., different universities may have different courses with the same id, e. g., "cs101") and likewise, studentid’s are unique only within a university (different universities may assign the same id to different students). suppose we want to answer certain queries approximately from a 1/20th sample of the data. for each of the queries below, indicate how you would construct the sample. that is, tell what the key attributes should be. (a) for each university, estimate the average number of students in a course. (b) estimate the fraction of students who have a gpa of 3.5 or more. (c) estimate the fraction of courses where at least half the students got "a."

the system of inequalities is

step-by-step explanation:

step 1

find the equation of the dashed line

we have the points

(0,0) and (3,1)

the line passes through the origin, so, is a direct variation

find the slope

the equation of the dashed line is

the solution of the inequality a s the shaded area above the dashed line

therefore

the equation of the inequality a is

step 2

find the equation of the solid line

we have the points

(4,0) and (0,4)

find the slope

the equation of the solid line is

the solution of the inequality b s the shaded area below the solid line

therefore

the equation of the inequality b is

step 3

the system of inequalities is

answer: what is the conflict?

step-by-step explanation:

*what has happened to new york city?

*what is in the time capsule?

* what did the kidz see that gave them hope?

*what will they do with what they find?

* how will they save the city?

* what challenges will they face along the way?

*what big choice will they make at the climax of the story?

* what lesson do they learn at the end of the story?