A survey of entrepreneurs who started companies last year shows that while virtually all did substantial preparatory research and planning, only half used that work to produce a formal business plan. Since, on average, the entrepreneurs without formal plans secured the capital they needed in half the time of those with plans, these survey results indicate that, in general, formal plans did not help the entrepreneurs who produced them to secure the capital they needed.

Which of the following, if true, most seriously weakens the argument?

【选项】The entrepreneurs who produced business plans generally reported later that the process of writing the plan had increased their confidence that their company would succeed.