It has been observed which some persons who suffer from common colds are diagnosed with it again in one year of first episode. This is due, in part, to damage from first episode. In order to examine the percentage of the persons who suffer from common colds a second time, a random sample of 600 people who suffered from common colds was collected and it was observed that 40 of them again suffered from common colds within one year. Select a 95% confidence interval for the true proportion of those who suffer a second episode.