Midterm scores in a class have an average of 75 and an SD of 8. Final exam scores in the class have an average of 50 and an SD of 10. The correlation between the two variables is 0.63 and the scatter diagram is football shaped.
Students complain that the final was too hard, so the instructor gives each student 15 more points on the final.

Question

Midterm scores in a class have an average of 75 and an SD of 8. Final exam scores in the class have an average of 50 and an SD of 10. The correlation between the two variables is 0.63 and the scatter diagram is football shaped.
Students complain that the final was too hard, so the instructor gives each student 15 more points on the final.

anonymous · Answer

The final exam is “graded on a curve,” with the top 20% of the students on the final receiving an A grade on the exam. Is the set of students who receive an A on the exam based on the new final exam scores different from the set of students who received an A on the exam based on the old final exam scores?


Yes.
No.
Maybe, or maybe not; there is not enough information to decide.

anonymous · Answer

no

anonymous · Answer

what is the correct answer?

anonymous · Answer

sorry for this one The correlation between the new final scores and the old final scores is:


-1
-0.63
0
0.63
1
impossible to determine based on the information given.
possible to determine based on the information given, and not equal to -1, -0.63, 0, 0.63 or 1.

anonymous · Answer

4a)  no
4b)  1
4c)  0.63

anonymous · Answer

The scatter diagram of the lengths and widths of the petals of a type of flower is football shaped; the correlation is 0.8. The average petal length is 3.1 cm and the SD is 0.25 cm. The average petal width is 1.8 cm and the SD is 0.2 cm.
 

6c: Of the petals that are 1.5 cm wide, about what percent are less than 2.75 cm long?

anonymous · Answer

Solution 
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