Suppose the weights of a population of female Siamese cats are normally distributed with an unknown population mean and a population standard deviation of 0.9 pounds. A random sample of Siamese cats from the population produces a sample mean weight of x=10.1 pounds. What value of z should be used to calculate a confidence interval with a 99% confidence level? z0.10 z0.05 z0.025 z0.01 z0.005 1.282 1.645 1.960 2.326 2.576