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  1. Prepare
  2. Mathematics
  3. Probability
  4. Day 4: Normal Distribution #2
  5. Discussions

Day 4: Normal Distribution #2

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8 Discussions

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  • aaron99ho
     + 0 comments
    import math

mean = 20 
std = 2

def calc_prob(lower_bound, upper_bound=None):
    if upper_bound is None:
        prob = 0.5 * (1 + math.erf((lower_bound - mean) / (std * math.sqrt(2))))
    else:
        prob = 0.5 * (math.erf((upper_bound - mean) / (std * math.sqrt(2))) -
                             math.erf((lower_bound - mean) / (std * math.sqrt(2))))  
    return prob

print(round(calc_prob(19.5), 3))

print(round(calc_prob(20,22), 3))

  • addsc7
     + 0 comments

    Here is my answer:

    # Enter your code here. Read input from STDIN. Print output to STDOUT
import math
def get_function(x):
    mu = 20
    sig = 2
    gaussian_func = (1 / (sig * math.sqrt(2 * math.pi))) * math.exp(-((x - mu) ** 2) / (2 * sig ** 2))
    return gaussian_func

start_value = 12
end_value = 28
step = 0.0001

x = [start_value + i * step for i in range(int((end_value - start_value) / step) + 1)]
y = 0
y1 = 0
y2 = 0

for i in range(len(x)):
    y += get_function(x[i]) * step
    if x[i] < 19.5:
        y1 += get_function(x[i]) * step

    if 20 < x[i] < 22:
        y2 += get_function(x[i]) * step

result1 = int((y1 / y) * 1000) / 1000
result2 = int((y2 / y) * 1000) / 1000

print(str(result1))
print(str(result2))

  • think_mark_think
     + 0 comments

    For anyone having conceptual trouble, check out these links:

    Fancy functions won't help you learn

  • davidwuelfert
     + 0 comments

    Hackerrank should be flagged as "unstable prototype".

    2 points I noted: The answers here have to be entered in the wrong order for the "Correct answer message". R code that works on any other machine, regularly fails on hackerrank. Pretty embarrassing for a website that claims to assess your IT skills.

  • vamshi_indla
     + 1 comment

    I submitted R code, it works fine in Rstudio and result is 0.401 and 0.341; but site says its incorrect. Am i missing anything?

    cat(round(pnorm(19.5,20,2),3));

    cat(round(pnorm(22,20,2),3) - round(pnorm(20,20,2),3))