def samplestand(data, sample_size):
dev = 0
sample = sampledata(data, sample_size)
sample_values = len(sample)
x_bar = mean()
x = sample_values
n = subtraction(sample_values, 1)
for dev in sample:
dev = subtraction(x, x_bar)
square_x_bar = square(dev)
add = addition(square_x_bar, square_x_bar)
result = division(add, n)
return squareroot(result)
def popstand(numbers):
num_values = len(numbers)
result = mean(numbers)
total = 0
for numb in numbers:
result2 = subtraction(numb, result)
sq = square(result2)
total = addition(total, sq)
return squareroot(division(num_values, total))
def confidence_interval(numbers):
num_value = len(numbers)
result = popstand(numbers)
result2 = squareroot(num_value)
sample_error = division(result2, result)
margin_error = multiplication(
1.96, sample_error) # 1.96=z_value for 95% confidence interval
result4 = addition(result, margin_error)
result5 = subtraction(margin_error, result)
return result4, result5
def stddev(nums):
var = variance(nums)
return squareroot(var)
def sqrt(self, a):
self.result = squareroot.squareroot(int(a))
return self.result
def squareroot(self, a):
self.result = squareroot(a)
return self.result
def square_rt(self, a):
self.result = squareroot(a)
return round(float(self.result), 7)