The following gives information about the proportion of a sample that agree with a certain statement. use statkey or other technology to find a confidence interval at the given confidence level for the proportion of the population to agree, using percentiles from a bootstrap distribution. statkey tip: use "ci for single proportion" and then "edit data" to enter the sample information. find a 90% confidence interval if 112 agree and 288 disagree in a random sample of 400 people.