7. A community college financial aid office wanted to estimate the proportion of all their students who had substantial credit card debt. A random sample of 200 students showed that 60 students had substantial credit card debt. Create a confidence interval at 95% confidence for the proportion of all students (at that college) who had substantial credit card debt.

8. A child development researcher wanted to estimate the population mean ( ) for the age (in weeks) at which babies start to crawl. A random sample of n = 45 babies showed a sample mean x = 36 weeks and sample standard deviation s = 4 weeks. Create a confidence interval at 95% confidence for the population mean .