Can anyone help me in this statistics homework? An environmental scientist wants to estimate the mean chloride content of a river stream by taking samples at different points of the river downstream....

Can anyone help me in this statistics homework?

1. 
   

   An environmental scientist wants to estimate the mean chloride content of a river stream by taking samples at different points of the river downstream.  The scientist obtains the following data of chloride content (mg/L) from his sample of 20 measurements at different parts.

   
   

   212,  167,  182,  175,  196,  165,  192,  210,  196,  167,  197,  188,  207,  187,  214,  203,  168,  189,  168  & 170.

   
   

   Construct an interval estimate of the true mean chloride content of the river using 95 % level of confidence.  Show your solution by uploading a picture of it.

   
   


2. The following data are readings (in foot-pounds) of the impact strengths of two kinds of packaging material :
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   

   material A	1.25	1.16	1.33	1.15	1.23	1.20	1.32	1.28	1.21
   material B	0.89	1.01	0.97	0.95	0.94	1.02	0.98	1.06	0.98

   
   

   a) Present an MS Excel generated table to determine whether there is evidence of a difference in the mean impact strengths for the two kinds of material.  Assume equal population variances.

   
   

   b) Fill up the following :

   
   

   Ho :

   
   

   H_A :

   
   

   Test Statistic Critical Value :

   
   

   Test Statistic Calculated Value :

   
   

   Decision :

   
   

   Conclusion :

   
   

   c)  What practical implications do the results of the statistical test tell us ?

   
   


3. 
   

   Coke is a solid fuel made by heating coal in the absence of air so that the volatile components are driven off.  For screened coke, the porosity factor is measured by the difference in weight between dry and soaked coke.  A certain supply of screened coke from a supplier is claimed to have a porosity factor of 1.8 kilograms.  Ten samples of the screened coke obtained from this supplier are tested for porosity factors and the results are as follows :

   
   

   1.7 ,  1.9 ,  1.8 ,  1.9 ,  2.1 ,  2.1 , 2.0 , 1.8 , 1.7 ,  2.0 .

   
   

   Is there sufficient evidence to indicate that the actual coke from the supplier is more porous than what is claimed?  Use   Assume that the porosity factor is a normally distributed variable.

   
   

   Use the following format in your presentation.  Show the values of the mean and the standard deviation which you calculate using the formulas or directly through your calculator stat or through Excel.

   
   

   Ho :

   
   

   H_A :

   
   

   Test Statistic Critical Value :

   
   

   Test Statistic Calculated Value : (show the formula used and the solution here.)

   
   

   Decision :

   
   

   Conclusion :