Dust mite allergies. A dust mite allergen level that exceeds 2 micrograms per gram...

Dust mite allergies. A dust mite allergen level that exceeds 2 micrograms per gram of dust has been associated with the development of allergies. Consider a random sample of four homes, and let x be the number of homes with a dust mite level that exceeds The probability distribution for x, based on a study by the National Institute of Environmental Health Sciences, is shown in the following table: