gistfile1.txt

### SETUP
require 'rspec'

RSpec.configure do |config|
  config.color = true
end

### LOGIC (fix me)

# Returns the average of all the numbers in the array
def average(numbers)
  unless numbers.nil? or numbers.empty?
    numbers.map(&:to_f).reduce(0,:+) / numbers.size
  end
end

### TEST CODE (don't touch me)

describe '#average' do
  it 'returns nil for empty array' do
    result = average([])
    expect(result).to be_nil
  end
  it 'returns nil when nil is passed in' do
    result = average(nil)
    expect(result).to be_nil
  end
  it 'returns 4 for 3,4,5' do
    result = average([3, 4, 5])
    expect(result).to eq(4)
  end
  it 'can handle numbers represented as strings' do
    result = average([10, '20', 30])
    expect(result).to eq(20)
  end
  it 'can handle floats' do
    result = average([1.0, 1.5, 2.0])
    expect(result).to eq(1.5)
  end
end

separate these into separate files in the gist. makes them easier to read.

I guess this is just you playing around with rspec but here's a question.
what do you expect average([,,'','10']) to give you?