D Suppose we are given a random sample of n=64 observations from a population with finite variance. This sample produced a sample mean of 16 and a sample standard deviation s=3. Find a 95% confidence interval for the population mean. O (13.53 , 18.47) (15.265 , 16.735) O (12.72 , 19.28) D 15) Suppose Y is distributed according to t-distribution with 11 degrees of freedom. find the value c such that P(Y c) = .01. O -3.106 -2.718 3.106 O 2.718 D The following data represent the age (in weeks) at which 10 randomly selected babies crawled for the first time. 43, 44, 42, 31, 38, 45, 36, 39, 50, 52 Suppose that the data is a random sample from a population with a normal distribution. Construct a 90 confidence interval for the average age at which babies first crawl. O (39.23, 44.77) (41.13, 42.87) O (38.33, 45.67) O (40.84, 43.16) D In a study, researchers wanted to estimate the true mean skidding distance along a new road in a European forest. The skidding distance (in meters) were measured at 20 randomly selected road sites. The 95% confidence interval constructed based on the data collected was (303.3, 413.6). A logger working on the road claims that the mean skidding distance is at least 425 meters. Does the confidence interval supports the loggers claim? O No, it does not support the claim. Yes, it supports the claim. D 1 5 In estimating a population mean with a confidence interval based on a random sample X1...,Xn from a Normal distribution with an unknown mean and a known variance, how the length of the confidence interval changes if we increase the sample size? Will decrease Will increase Remains the same