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In: Statistics and Probability

Twelve samples of water from a particular source have an average lead concentration of 12.5μg/L with...

  1. Twelve samples of water from a particular source have an average lead concentration of 12.5μg/L with a standard deviation of 2.0μg/L. The 95% confidence interval for the lead concentration in water from this source is approximately

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Expert Solution

We have given that,                      
                      
Sample mean =12.5 μg/L              
Sample standard deviation =2 μg/L          
Sample size =12              
Level of significance=0.05              
Degree of freedom =11              
                      
t critical value is (by using t table)=2.201              
                      
Confidence interval formula is                       


=(11.2,13.8)                  
                      
                      
Lower confidence limit=11.2 μg/L          
                      
Upper confidence limit=13.8 μg/L             

orchestra answered 2 years ago
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