Researchers want to know if the concentration of ammonia in the James River is above the safe level for consumption. They take samples and develop a data set. Their null hypothesis is that the sample mean is > 6(unsafe) and their alternative hypothesis is that the sample mean is < 6. Which of the following should they use in testing their hypothesis?

A) a one-tailed test

B) a two-tailed test

in the year 2850, humans successfully colonized mars. the martian modules that were constructed could hold only a small population of people. it is now a century later, and the population on mars has grown to 600 people. of the current mars population, 45 people express the recessive phenotype for phenylketon- uria (pku) syndrome (pp genotype).

explanation:

the answer is true when observing or determining population size, a direct observation is use, in which each organism is counted in a population or in an area. one benefit of this measure is that you get the exact population count but it will take a long time to  determine  the  size  of a  population.

the answer

b.) bowling ball