Question

Score: 0 of 4 pts 9.4.83-P EQuestion Help Cadmium, a heavy metal, is toxic to animals. Mushrooms, however, are able to absorb and accumulate cadmium at high concentrations. A govemment set a safety imit for cadmium in dry vegetables at 0.5 parts per million (ppm). The cadmium levels in a random sample of one species of edible mushroom are in the accompanying data set AZ the 5% significance level do te data pro de su cent evidence to conclude that the mean cadmium level in this species o mushroom is greater than the governments recommended limit of 05 ppm? Assumาอ that the population standard deviation of cadmim levels in this species of mushroom is 0.42 ppm. Preliminary data analyses indicale that applying the z-test is reasonable. (Note: The sum of the data is 8.31 ppm.) Click.here to.viewtecadmisum.concentration data Ch迭hereto yen Page lof te table ot aceasunderrestandardnormalane. State the hypotheses for the one-mean z-test (Type integers or decima's. Do not round.)

Answer 1

Hypotheses are:

Here sample size is not given. Let us assume sample size is n. The sample mean is

Here z test statistics will be used. The test statistics is

$z=rac{ar{x}-mu}{sigma/sqrt{n}}=rac{ar{x}-0.5}{0.42/sqrt{n}}$

Test is right tailed. So critical values of z for 0.05 level of significance are +/- 1.96. Rejection region:

If z < -1.96 or z > 1.96,reject H0