Periodically, the county water department tests the drinking water at its water distribution center. officials want to determine if the mean lead level at the center exceeds the epa action level of 15 ppb. to do so, they take 10 samples of water and test each for lead. (1) what is the scientific hypothesis?

a. the mean lead level is less than the epa action level.
b. the mean lead level exceeds the epa action level.
c. all 10 measurements are less than the epa action level.
d. the mean lead level equals the epa action level.

what is the statistical model?
a. one population normal
b. one population binomial
c. paired normal populations
d. two independent binomial populations
e. two independent normal populations

what are the statistical hypotheses?
a. h0: μ=15 ppm; ha: μ< 15 ppm.
b. h0: μ=15 ppm; ha: μ≠15 ppm.
c. h0: μ=15 ppm; ha: μ> 15 ppm.
d. none of the above.