Historically it has taken a local council an average of 18 weeks to reach a decision about planning applications for building development work submitted by construction companies. The companies have complained that decisions are taking too long and delays are costing them money. The chief executive of the local council has initiated a streamlined system for such applications with the intent of reducing the time taken to reach a decision. After a few months’ operation, a sample of 250 planning applications has been analysed and a mean time of 15 weeks found, with a standard deviation of 5.2 weeks. Has the streamlined system led to a reduction in mean time taken?