In a study of 420 056 cell phone users 124 subjects develope

In a study of 420, 056 cell phone users, 124 subjects developed cancer of the brain or nervous system. Test the claim of a somewhat common belief that such cancers are affected by cell phone use. That is, test the claim that cell phone users develop cancer of the brain or nervous system at a rate that is different from the rate of 0.0340% for people who do not use cell phones. Because this issue has such great importance, use a 0.001 significance level. Identify the null hypothesis, alternative hypothesis, test statistic, P-value, conclusion about the null hypothesis, and final conclusion that addresses the original claim. Use the P-value method and the normal distribution as an approximation to the binomial distribution.

What is the test statistic ? z=_____ - round to two decimal places (how do you find it in the calculator and what values do you input in a ti83 plus calculator)

What is the P-value? P value=____ round to four decimal places ( how do you find it in the calculator and what values do you input in a ti83 plus calculator)

Solution

Formulating the null and alternatuve hypotheses,          
          
Ho:   p   =   0.00034
Ha:   p   =/=   0.00034
As we see, the hypothesized po =   0.00034      
Getting the point estimate of p, p^,          
          
p^ = x / n =    0.000295199      
          
Getting the standard error of p^, sp,          
          
sp = sqrt[po (1 - po)/n] =    2.84454E-05      
          
Getting the z statistic,          
          
z = (p^ - po)/sp =    -1.574991641 = -1.57   [ANSWER, TEST STATISTIC]  

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As this is a    2   tailed test, then, getting the p value,  
          
p =    0.115258374   [ANSWER, P VALUE]  

You can use the normcdf(-1E99, -1.574991641, 0, 1) to get the left tailed area, then multiply it by 2 as this is two tailed. You will get the P value above.