Expected Record Values

Problem

Expected number of records (left-to-right maxima) in n independent continuous observations:

E[records] = H_n = 1 + 1/2 + ... + 1/n.

The k-th observation is a record with probability 1 / k. Return 0.0 for n <= 0.

Hint

Use indicators and linearity of expectation.

case 1

in: [1]

expected: 1

case 2

in: [2]

expected: 1.5

case 3

in: [5]

expected: 2.283333333333333

case 4

in: [0]

expected: 0

Starter codePython

def expected_records(n):
    # Your code here
    pass

4 test cases · run your code against them in the editor