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Python Math: Describe linear regression

Python Math: Exercise-61 with Solution

Write a Python program to describe linear regression .

Note : A linear regression line has an equation of the form Y = a + bX, where X is the explanatory variable and Y is the dependent variable. The slope of the line is b, and a is the intercept (the value of y when x = 0).

Sample Solution:-

Python Code:

#https://gist.github.com/cartr/6513044
# Define the data
data = set()
count = int(input("Enter the number of data points: "))
for i in range(count):
    x=float(input("X"+str(i+1)+": "))
    y=float(input("Y"+str(i+1)+": "))
    data.add((x,y))

# Find the average x and y
avgx = 0.0
avgy = 0.0
for i in data:
    avgx += i[0]/len(data)
    avgy += i[1]/len(data)

# Find the sums
totalxx = 0
totalxy = 0

for i in data:
    totalxx += (i[0]-avgx)**2
    totalxy += (i[0]-avgx)*(i[1]-avgy)

# Slope/intercept form
m = totalxy/totalxx
b = avgy-m*avgx

print("Best fit line:")
print("y = "+str(m)+"x + "+str(b))

x = float(input("Enter a value to calculate: "))
print("y = "+str(m*x+b))

Sample Output:

Enter the number of data points: 2                                                                            
X1: 1                                                                                                         
Y1: 2                                                                                                         
X2: 3                                                                                                         
Y2: 4                                                                                                         
Best fit line:                                                                                                
y = 1.0x + 1.0                                                                                                
Enter a value to calculate: 10                                                                                
y = 11.0

Flowchart:

Flowchart: Find the roots of a quadratic function

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Python: Tips of the Day

Getting rid of unwanted characters:

You can get rid of whitespaces or any specific character using strip methods in Python. You can use either plain strip for both sides, lstrip for the left side and rstrip for the right side only.

str="+++Welcome python+++"
str.strip()

print(str)

Output:

+++Welcome python+++