1. A study of 500 randomly selected nurses in a particular state shows the mean age of the nurses to be 43.1 years with

[answerhappygod]

1. A study of 500 randomly selected nurses in a particular state
shows the mean age of
the nurses to be 43.1 years with a standard deviation of 10.6
years. Find a 99%
confidence interval for the mean age.
2. A new test has been developed for measuring night vision
achieved by Marines. How
many Marines must be tested if the sample mean is to be estimated
within 2 points with
a 98% confidence and a previous study suggests that the population
standard deviation
is 10.7?
3. A nutritional specialist finds that 520 of 760 children
eat an afternoon snack. Find the
99% confidence interval for the true population of all children who
also eat snacks.
4. You wish to estimate the percentage of US employees who
have been with their
current employer for two years or more. What size sample should you
take if you must
be 95% sure that you are within 2.5 percentage (.025) points
if:
a. No preliminary estimation of the proportion has been made.
b. You find that the US Department of Labor suggests the true
percentage is
approximately 39%.