Investigators took a random sample of 100 crew members of Xi…

Investigators took a random sample of 100 crew members of Xinjiang Airlines who wore radiation detectors and reported an average exposure of 219 mrems (millirems) of radiation with a standard deviation of 20 mrems.  What is the standard error of the sample mean?  (Round your answer to the nearest whole number.)

Refrigerators are usually fairly accurate, but the true temp…

Refrigerators are usually fairly accurate, but the true temperature has some variability from what is stated on the thermometer inside.  A 95% confidence interval for the true temperature of a refrigerator thermometer set at 40°F is (35.50 and 41.25).  What is the margin of error?  (Round your answer to 2 decimal places.)

Environmentalists studying the effect of fire on the nutrien…

Environmentalists studying the effect of fire on the nutrients in soil measured the calcium level in randomly selected soil samples for 8 plots before and after a prescribed burn. Before the burn, the mean calcium level was 66.8 kg/plot, and the standard deviation was 14.65 kg/plot.  Here are the measurements for these plots after the burn:       9,    18,   36,   24,   18,   12,   25,   26  The type of graph being used to display calcium levels after the burn is called a [a]. The shape of the distribution of calcium levels after the burn is [b]. The environmentalists conducting the study want to estimate the mean calcium level after the burn using these eight randomly selected after-burn soil samples. To do so, they should use a(n) [c].