2. Arsenic is a compound that occurs naturally in very low concentrations. Arsenic blood concentrations in healthy individuals are Normally distributed, with a mean of 3.2 mg/dl and a standard deviation of 1.5 mg/dl. A researcher believes that one area of the United States has naturally elevated arsenic levels in the ground and water supplies. An SRS of 25 individuals in this area found a sample mean arsenic level of 3.75 mg/dl. What are the null and alternative hypotheses for this study?

Respuesta :

Answer:

The null hypothesis                 [tex]H_o : \mu = 3.2 \ mg/dl[/tex]

The alternative hypothesis      [tex]H_a : \mu > 3.2 \ mg/dl[/tex]

Step-by-step explanation:

From the question we are told that

  The mean is  [tex]\mu = 3.2 \ mg/dl[/tex]

   The standard deviation is [tex]\sigma = 1.5 mg/dl[/tex]

   The sample size is  n = 25

    The sample mean is  [tex]\= x = 3.75 \ mg /dl[/tex]

Generally

   The null hypothesis is : That the mean of the  Arsenic blood concentrations in healthy individuals is [tex]\mu = 3.2 \ mg/dl[/tex]

i.e

The null hypothesis  [tex]H_o : \mu = 3.2 \ mg/dl[/tex]

    The alternative hypothesis is : That the mean of the  Arsenic blood concentrations in healthy individuals is greater than  [tex]\mu = 3.2 \ mg/dl[/tex]

The alternative hypothesis      [tex]H_a : \mu > 3.2 \ mg/dl[/tex]