Instructions: After the student calculates the answers to this homework he/she m
ID: 3350239 • Letter: I
Question
Instructions: After the student calculates the answers to this homework he/she must submit the answers by placing them in the Assignment # _ Submittal Link in Bb by midnight of the date shown in the Course Roadmap and Syllabus. The Instructor does not allow late submissions therefore a score of zero (0) will be recorded for the assignment if submitted after midnight Eastern Time of the due date. Solutions for the assignment will be released in Bb the morning after the due date for access by students. Total points for the assignment is 100. Note: There is no partial credit given; either the answer is correct or incorrect. After you have submitted your answers in the Assignment #_ Submission Link, upload the Excel file (provided you by the Instructor) containing your answers and calculations into the Home Work #_ Supporting Documentation Submission link prior to the due date and time. As stated in the syllabus a score of zero will be awarded for the assignment if this Excel file is not submitted. Scenario: The head of the chemistry department at a local university has tasked a student teaching assistant to prepare a variety of statistics pertaining to the final course grades earned by students who have completed the university’s CHEM 103 course during the past ten years. These statistics will be used as a basis for predicting the potential performance of future students who enroll in the course. A total of 1,125 students have completed the course during the past ten years. Rather than trying to have the teaching assistant collect and analyze data for all 1,125 students, the department head has agreed to allow the teaching assistant to prepare the necessary statistics using a small random sample consisting of 25 students who completed the course during the past ten years. The following table summarizes the final course grades earned by the 25 randomly selected students. Student No. Course Grade Student No. Course Grade 1 83.17 14 86.76 2 82.31 15 74.23 3 90.18 16 86.89 4 92.87 17 88.57 5 89.56 18 96.93 6 96.06 19 86.48 7 83.75 20 99.58 8 85.17 21 92.32 9 86.67 22 78.70 10 86.35 23 92.67 11 83.11 24 74.56 12 82.16 25 78.48 13 89.48 Data: For the purposes of this assignment, assume that: (1) the small sample consisting of 25 students is truly representative of the population of 1,125 students from which it was drawn; and (2) the 1,125 students who have completed the course during the past ten years constitute a truly representative sample of all future students who will eventually enroll in the course. Based upon these assumptions, use the sample data provided in the preceding table to answer the following questions. This HW is worth a total of 100 total points. The points for each question may vary. Data: Using the previously provided sample data for the final course grades earned by the 25 randomly selected students, determine the frequency, relative frequency and cumulative frequency for each of the following eleven grade classes. Grade Classes Grade Classes 0.00-10.00 60.00-70.00 10.00-20.00 70.00-80.00 20.00-30.00 80.00-90.00 30.00-40.00 90.00-100.00 40.00-50.00 100.00 or more 50.00-60.00 Question 9. Assuming that student grades would theoretically be symmetrically distributed around the 70.00 – 80.00 grade class, does the histogram indicate that the distribution of actual student grades is skewed (either positively skewed or negatively skewed)? (3 points) Question 10. Which grade class evidences the highest frequency of actual student grades? (3 points) Question 11. What is the relative frequency for the 70.00 – 80.00 grade class? (3 points) Question 12. What is the cumulative frequency for the 80.00 – 90.00 grade class? (3 points)
Explanation / Answer
Q9
Class Interval
(Grade)
Frequency (f)
Relative Frequency (r)
Cumulative Frequency (F)
[0 – 10)
0
0
0
[10 – 20)
0
0
0
[20 – 30)
0
0
0
[30 – 40)
0
0
0
[40 – 50)
0
0
0
[50 – 60)
0
0
0
[60 – 70)
0
0
0
[70 – 80)
4
0.16
4
[80 – 90)
14
0.56
18
[90 – 100)
7
0.28
25
100 and more
0
0
25
Total
25
1.0
-
Note: [ => inclusion, ) => exclusion
Q10
Highest frequency is observed in the grade class: [80 – 90) ANSWER
Q11
Relative frequency for the grade class, [70 – 80) is: 4 ANSWER
Q12
Cumulative frequency for the grade class, [80 – 90) is: 18 ANSWER
Class Interval
(Grade)
Frequency (f)
Relative Frequency (r)
Cumulative Frequency (F)
[0 – 10)
0
0
0
[10 – 20)
0
0
0
[20 – 30)
0
0
0
[30 – 40)
0
0
0
[40 – 50)
0
0
0
[50 – 60)
0
0
0
[60 – 70)
0
0
0
[70 – 80)
4
0.16
4
[80 – 90)
14
0.56
18
[90 – 100)
7
0.28
25
100 and more
0
0
25
Total
25
1.0
-
Note: [ => inclusion, ) => exclusion