Question

In a study published in the American Journal of Psychiatry researchers wanted to measure the effect of alcohol on the development of the hippocampal region (responsible for long term memory storage) in adolescents. The researchers randomly selected 12 adolescents with alcohol use disorders. They wanted to determine whether the hippocampal volumes in the alcoholic adolescents were less than the normal volume of 9.02 cubic centimeters HA:μ<9.02 . An analysis of the sample data revealed that the hippocampal volume is approximately normal with mean 8.10 and standard deviation 0.7. Which of the following is true about the P-value?

Answer 1

Null hypothesis      

               
                      
Alternative hypothesis         

           
                      
We have for given sample,                      
Population mean for given sample=9.02      
Sample mean=8.1              
Sample standard deviation s=0.7          
Sample size =n=12              
                      
Degree of freedom = n-1 =11          
                      
      
                      
t test statistic formula is

P value is 0.0004.....................by using Excel command TDIST(-4.55,11,1)