help

#1
Working on some practice problems for a test. Really new to statistics, been out of college for a while. I am struggling with the wording...just looking for a place to start and then I can work the problems and post what I come up with...

1. Ralph Lauren wants to research the age of people the purchase their jeans in LA. They took a random sample and found that of the 30 people they samples, the average age of people purchasing Ralph Lauren jeans was 30.5 years old with a standard deviation of 4.94 years. Help them construct a 95%confidence interval for the data.
- I set it up as this: 30.5 +/- 1.96 (4.94/sq rt of 30)
- answers 28.718 , 32.282


2. A cattle rancher is interested in using a newly developed hormone to increase the weight of beef cattle. Before investing in this hormone, the rancher would like to obtain some estimate of its effect. Without the hormone, the cattle weigh an average of 1250lbs when they are sold at 8 months old. the distribution of weights is approximately normal with standard dev. = 80. A sample of 16 calves is selected to test the hormone. At age 8 months, the avg weight for this sample is 1340lbs. Make an interval estimate of the pop mean so that you are 95% confident that the true mean is in your interval.
- I set it up as 1340 +/- 1.96 (80/sq rt of 14)
- answers 1300.8 , 1379.2


Any help on if i even went after these correctly would be greatly appreciated!