IE STAT 1 -STATISTICAL ANALYSIS FOR IE 1 ACTIVITY 5 Name: Date: Course & Section: Score: Solve the following problems. 1. A random sample of size 144 is drawn from a population whose distribution, mean, and standard deviation are all unknown. The summary statistics are X=58.2 and s = 2.6. Construct an 80% confidence interval for the population mean u. 2. A random sample is drawn from a normally distributed population of unknown standard deviation. Construct a 99% confidence interval for the population mean based on the information given. n = 18, X=386, s = 24 3. A thread manufacturer tests a sample of eight lengths of a certain type of thread made of blended materials and obtains a mean tensile strength of 8.2 lb with standard deviation 0.06 lb. Assuming tensile strengths are normally distributed, construct a 90% confidence interval for the mean tensile strength of this thread 4. A corporation that owns apartment complexes wishes to estimate the average length of time residents remain in the same apartment before moving out. A sample of 150 rental contracts gave a mean length of occupancy of 3.7 years with standard deviation 1.2 years. Construct a 95% confidence interval for the mean length of occupancy of apartments owned by this corporation. 5. In a random sample of size 1,100, 338 have the characteristic of interest. Construct an 80% confidence interval for the population proportion p