Question

A botanist wishes to estimate the typical number of seeds for a certain fruit. She samples 68 specimens and counts the number of seeds in each. Use her sample results (mean = 21.8, standard deviation = 9.7) to find the 90% confidence interval for the number of seeds for the species. Enter your answer as an open-interval (i.e., parentheses) accurate to 3 decimal places.  

90% C.I. =

Answer 1

We have given that,          
          
Sample mean =21.8  
Sample standard deviation =9.7
Sample size =68  
Level of significance=1-0.90=0.1  
Degree of freedom =67  
          
t critical value is (by using t table)=   1.668  
          
Confidence interval formula is   

=(19.838,23.762)      

Therefore, 90% Confidence interval is =  (19.838,23.762)