10.18 Employees of a building materials chain in Monaco who were facing a shutdown were surveyed on a prospective employee ownership plan. Some employees pledged €10,000 to this plan, putting up €1,000 immediately, while others indicated that they did not intend to pledge. Of a random sample of 254 people who had pledged, 108 had already been laid off, whereas 226 of a random sample of 680 people who had not pledged had already been laid off. Test, at the 5% level against a two-sided alternative, the null hypothesis that the population proportions already laid off were the same for people who pledged as for those who did not.