2. Calculate the standard deviation of the following sample: 67,89,45,56,102,345 Group of answer choices 103.59 134 113.48 100

3. For a random sample of 30 business days from January 4, 2010, through February 24, 2017, U.S. gold prices had a sample mean of $1256.48. The population standard deviation is estimated to be $208.90. Find a 90% confidence interval for the population mean. Group of answer choices 1193.94 to 1319.02 1189.93 to 1344.42 1145.55 to 1233.33 1123.34 to 1234.45