Question

Write a Python Program

Preview File Edit View Go Tools Window OO 95% Help An Intro to Programming Using Python (2) (1) (1).pdf (page 256 of 431) Mon 11:28 AM Q E © Q Search 2. Curve Grades Statisticians use the concepts of mean and standard deviation to describe a collection of numbers. The mean is the average value of the numbers, and the standard deviation measures the spread or dispersal of the numbers about the mean. Formally, if X1, X1, X3,...,x, is a collection of numbers, then the mean is S An Intro to Programming Using Python (2) (1) (1).pdf Cover Title Page Copyright Page Guide to Video Notes Guide to Application Topics Contents Preface Acknowledgments Chapter 1: An Introduction to Computing and Problem Solving Chapter 2: Core Objects, Variables, Input, and Output Chapter 3: Structures That Control Flow ► Chapter 4: Functions Chapter 5: Processing Data 5.1: Processing Data, Part 1 5.2: Processing Data, Part 2 5.3. Dictionaries Key Terms and Concepts Programing Projects Chapter 6: Miscellaneous Topics ► Chapter 7: Object Oriented Programming Chapter 8: Graphical User Interface Appendices Programming Projects . 239 and the standard deviation is (x - m) + (x2 - m.) + (x3 - m)2 + ... + (x,- m)? The file scores txt contains exam scores. The first four lines of the file hold the num bers 59, 60, 65, and 75. Write a program to calculate the mean and standard deviation of the exam scores, assign letter grades to each exam score, ES, as follows, and then display information about the exam scores and the grades, as shown in Fig. 5.48. Answers ES > m + 1.55 m + 55 SES <m + 1.5s m- .5s S ES <m+.5s m - 1.55 SES <m - 5s ES <m - 1.55 Index Number of scores: 14 Average score: 71.0

Answer 1

Python Code:

import math

# this function calculates the mean of the list l
def calc_mean(l):
   return sum(l)/len(l)

# this function calculates the stadard deviation of the list l
def calc_stdDev(l):
   m = sum(l)/len(l) # mean
   n = len(l) # number of elements in the list
   temp = 0

   # calculate sum of squared diff. from mean
   for i in l:
       temp+=(i-m)**2

   return math.sqrt(temp/n)  

# this function calculates the grade of the student depending on the exam score, mean and stdDev
def assign_grade(EX,m,s):
   if EX >= (m+1.5*s):
       return 'A'
   elif EX >= (m+0.5*s) and EX < (m+1.5*s):
       return 'B'
   elif EX >= (m-0.5*s) and EX < (m+0.5*s):
       return 'C'
   elif EX >= (m-1.5*s) and EX < (m-0.5*s):
       return 'D'
   elif EX < (m-1.5*s):
       return 'F'

# main function
def main():
   file_object = open('Scores.txt') # open the file
   # the elements in the text file are exam scores of students, one score per line
   list_of_scores = []
   num_of_scores = 0
   for item in file_object.readlines():
       exam_score = int(item.split('\n')[0])
       list_of_scores.append(exam_score)
       num_of_scores+=1

   m = calc_mean(list_of_scores) # mean
   s = calc_stdDev(list_of_scores) # standard deviation  
  
   # print the mean and standard deviation
   print("Number of scores: "+str(num_of_scores))
   print("Average of scores: "+str(m))
   print("Standard Deviation of scores: "+str(s))

   # print out the grade of the students
   for i in range(num_of_scores):
       grade = assign_grade(list_of_scores[i],m,s)
       print("Exam score: "+str(list_of_scores[i])+", Grade:"+grade)

if __name__ == '__main__':
   main()          

Code Snapshot:

import math # this function calculates the mean of the list i def calc_mean(l): return sum(L)/len(1) # this function calculates the stadard deviation of the list i def calc stdDev (l): m = sum(L)/len(l) # mean n = len(l) # number of elements in the list templenteni # calculate sum of squared diff. from mean for i in 1: temp+=(i-m) **2 return math.sqrt(temp/n) # this function calculates the grade of the student depending on the exam score, mean and stdDev def assign_grade(EX,m,s): if EX >= (m+1.5*s): return 'A' elif EX >= (m+0.5*5) and EX < (m+1.5*5): return 'B elif EX >= (m-0.5*5) and Ex < (m+0.5*s): return 'C' elif EX >= (m-1.5*s) and EX < (m-0.5.5): return 'D' elif EX < (m-1.5*5): return 'F'

# main function def main(): file object = open('Scores.txt') # open the file # the elements in the text file are exam scores of students, one score per line list of scores = [1] num of scores = 0 for item in file_object.readlines(): exam_score = int(item.split('\n')[0]). list_of_scores.append(exam_score) num_of_scores+=1 m = calc mean(list of scores) # mean S = calc stdDev (list of scores) # standard deviation # print the mean and standard deviation print("Number of scores: "+strinum of scores)), print("Average of scores: "+str(m)) print("Standard Deviation of scores: "+stris), # print out the grade of the students for i in range(num_of_scores): grade = assign grade(list of scores[im,s), print("Exam score: "+str(list of scores[i])+", Grade: "+grade) if name main() == 'main ':

Output:

Number of scores: 14 Average of scores: 68 Standard Deviation of scores: 14.3527000944 Exam score: 59, Grade:D Exam score: 60, Grade:D Exam score: 65, Grade:C Exam score: 75, Grade: C Exam score: 80, Grade: B Exam score: 95, Grade: A Exam score: 72, Grade: C Exam score: 56, Grade:D Exam score: 49, Grade:D Exam score: 88, Grade:B Exam score: 57, Grade:D Exam score: 91, Grade: A Exam score: 64, Grade: C Exam score: 53, Grade:D