The composition of the earth's atmosphere may have changed over time. One attempt to discover the nature of the atmosphere long ago involved measuring the gas trapped in bubbles inside ancient amber. Amber is tree resin that has hardened and been trapped in rocks. Measurements on nine amber specimens from the late Cretaceous era (95 to 65 million years ago) give the following percentages of nitrogen:

63.4, 65.0, 64.4, 63.3, 54.8, 68.5, 60.8, 59.1, 51.0

Assume that it is reasonable to regard these trapped gas bubbles as a random sample of bubbles from the Cretaceous atmosphere.

State the values of the sample mean, the standard error, and the number of degrees of freedom. (2 decimal places)

b)Determine a 95% confidence interval to estimate the mean percent of nitrogen in the Cretaceous atmosphere. (Enter the lower endpoint, then the upper endpoint using 2 decimal places ##.##).

2)In an analysis of hunting by African lions, biologists filmed prey captures from the safety of their vehicles. The capture of prey was divided into a sequence of events for study, one of which is the stalk, defined as the reduction of predator-prey distance for prey that has been specifically located and the prey is unaware of or minimally alarmed by the predator. The investigators identified two types of stalk: (a) "crouching," -- the lion is concealed and either the lion advances toward the prey or the prey advances (unaware) toward the lion, and (b) "running," -- the lion is less concealed and advances toward the prey in a rapid manner. In a random sample of 151 lion stalks of Thomson's and Grant's gazelles the mean time was 24.9 minutes with a standard deviation of 3.0 minutes. It is believed that the actual mean stalking time is 25.6 minutes. What are the values of the test statistic (t) and the P-value (3 decimal places #.###)?