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Chapter 8: Q. 9.15 (page 358)

Toxic Mushrooms? Cadmium, a heavy metal, is toxic to animals. Mushrooms, however, are able to absorb and accumulate cadmium at high concentrations. The Czech and Slovak governments have set a safety limit for cadmium in dry vegetables at 0.5 part per million (ppm). M. Melgar et al. measured the cadmium levels in a random sample of the edible mushroom Boletus pinicola and published the results in the paper "Influence of Some Factors in Toxicity and Accumulation of Cd from Edible Wild Macrofungi in NW Spain" (Journal of Environmental Science and Health, Vol. B33(4), pp. 439-455). A hypothesis test is to be performed to decide whether the mean cadmium level in Boletus pinicola mushrooms is greater than the government's recommended limit.

Short Answer

Expert verified

Part (a). 0.5 mm

Part (b). greater the 0.5ppm

Part (c). right-tailed test

Step by step solution

01

Part (a) Step 1. Given information.  

The Czech and Slovak governments have set a 0.5 part per million cadmium safety standard for dry vegetables (ppm).

02

Part (a) Step 2. Determine the null hypothesis.  

Let cadmium levels in Boletus pinicola mushrooms be equal to μ.

The null hypothesis :

The average cadmium concentration in Boletus pinicola mushrooms is 0.5 mm.

03

Part (b) Step 3. Determine the alternative hypothesis.  

The alternative hypothesis:

The average cadmium concentration in Boletus pinicola mushrooms is greater than 0.5ppm.

Ha:μ>0.5ppm

04

Part (c) Step 4. Classify the hypothesis test as two tailed, left tailed, or right tailed.  

The right-tailed alternative hypothesis test is used to determine whether the mean cadmium levelling Boletus pinicola mushrooms is greater than 0.5ppm.

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