【判断题】If the population distribution is unknown, in most cases the sampling distribution of the mean can be approximated by the normal distribution if the sample size is at least 15 observations
【单选题】If the population of the earth goes on increasing at its current rate, there will eventually not be enough resources left to sustain life in the planet. By the middle of the 21 st century, if present ...
【单选题】In performing hypothesis tests about the population mean, if the population standard deviation is not known, a t test can be used to test the mean if _________________.
【单选题】In finding a confidence interval for the population mean, the population standard deviation should be used if it is known. If the population standard deviation is not known, then it should be estimate...