3. Heights of 1-year-old girls are Normally distributed, with mean 30 inches and standard deviation of 1.2 inches. A company claims that taking 500 mg of vitamin C makes girls taller. In a random sample of 100 baby girls who were given 500 mg vitamin C daily from birth to 1 year, the mean height was 30.1 inches. Is this evidence for the company’s claim? Assume the standard deviation remains the same. To make this determination, calculate and interpret the p-value for the appropriate test.

Respuesta :

Answer:

The p- value  is [tex]p-value  =  0.2033[/tex]

Its interpretation is  

As  [tex]p-value > \alpha[/tex]

The decision rule is

Fail to reject the null hypothesis

 The conclusion is  

There is no  sufficient evidence to support the  company claims at a level of  sign9ificance of 0.05

Step-by-step explanation:

From the question we are told that

  The mean is  [tex]\mu =  30 \  inches[/tex]

  The standard deviation is   [tex]\sigma  =  1.2 \  inches[/tex]

  The sample size is  n  =  100

  The sample mean is  [tex]\= x  =  30.1[/tex]

Let assume the level of significance is  [tex]\alpha = 0.05[/tex]

The null hypothesis is [tex]H_o  :  \mu \le 30[/tex]

The alternative is  [tex]H_a : \mu > 30[/tex]

Generally the test test is mathematically represented as

    [tex]z =  \frac{\= x- \mu }{\frac{\sigma}{\sqrt{n} } }[/tex]

=>  [tex]z =  \frac{30.1- 30 }{\frac{1.2}{\sqrt{100} } }[/tex]

=>  [tex]z =  0.83[/tex]

Generally from the z-table  the  probability of (Z > 0.83 ) is

   [tex]p-value  =  0.2033[/tex]

From the value obtained we see that  [tex]p-value > \alpha[/tex] hence

 The decision rule is

Fail to reject the null hypothesis

 The conclusion is  

There is no  sufficient evidence to support the  company claims at a level of  sign9ificance of 0.05