Simple script to post answer for http://stackoverflow.com/q/14527556/841064

test.html

<table>
  <tr>
    <td>Sara</td>
    <td>2.3</td>
    <td>4.3</td>
  </tr>
  <tr>
    <td>Mike</td>
    <td>4.5</td>
    <td>1.1</td>
  </tr>
  <tr>
    <td>Alex</td>
    <td>1</td>
    <td>8</td>
  </tr>    
</table>

test.rb

require 'capybara'
require 'capybara/dsl'
require 'rspec/expectations'

Capybara.app_host = "file:///path/to/folder/with/file"
Capybara.run_server = false
Capybara.current_driver = :selenium

include Capybara::DSL # It's a bad practice in general but good enough for simple script
include RSpec::Matchers

visit '/test.html'

def cell_text(n)
  find(:xpath, "./td[#{n}]").text
end

h = {2 => 4.5, 3 => 1.1}

within 'table' do
  all('tr').each do |row|
    within row do
      if cell_text(1) == 'Mike'
        h.each { |i, value| cell_text(i).should == value.to_s }
      else
        h.each { |i, value| cell_text(i).should_not == value.to_s }
      end
    end
  end
end