1. Assume that the standard deviation of college student IQ's is 10. A random sample of 100 students from a college showed an average IQ of 110. Compute a 95% confidence interval for the mean IQ of students attending this college.
2. In the Idaho State Home for Runaway Girls, 25 residents were polled as to what age they ran away from home. The sample mean was 16 year old and the sample deviation was 1.9 years. Compute a 95% confidence interval for the mean age at which runaway girls leave home in Idaho.
3. The nicotine content of five cigarettes of a brand measured in milligrams are 21,19,23,19,24. Compute a 0.99 confidence interval for the average nicotine content of the brand.