Question

9. Multiple Choice Question A sample of 20 fish are captured in lake A and their concentrations of polychlorinated biphenyl are measured using a certain technique. Furthermore, 15 fish are captured in lake B and and their concentrations of polychlorinated biphenyl are measured. The data (in parts per million) are summarized as follows: Lake A Lake B 12.42 12.50 1.167 15 mean standard deviation sample size Boxplots are constructed for each lake: 1.141 20 15 14 13 polychlorinated biphenyl (ppm) 12 11 Lake A Lake B Is it reasonable to assume that A. the populations are normal with equal variances B. the populations are normal with unequal variances C. only one of the populations is normal D. the populations are not normal E. none of the preceding

Answer 1

From the given,

We can see that box plot for lake A is symmetic but the box plot for lake B is skewed.

Hence using box plot,

We can say that,

Only one of the population is normal.

Which is of lake A.