$($b$)$ In a ready mix plant, cylindrical samples are prepared and tested periodically to detect any mix design problems and to ensure that the compressive strength is higher than the lower specification limit$.$ The minimum target value for compressive strength was set at $4000.$ The following compressive data were collected.

$\backslash$table$[[$Sample No$.,\backslash$table$[[$Compressive$],[$Strength$,$ psi$]],$Sample No$.,\backslash$table$[[$Compressive$],[$Strength$,$ psi$]]],[1,4915,14,5772],[2,4732,15,4270],[3,5670,16,5096],[4,4310,17,4670],[5,6110,18,5174],[6,4316,19,5434],[7,5240,20,3692],[8,4950,21,4510],[9,5230,22,3680],[10,4190,23,4100],[11,5770,24,3680],[12,4524,25,3910],[13,4056,,]]$

Calculate the mean, standard deviation, confidence interval $(Cl),$ and the coefficient of variation of the test data. Is the plant production meeting the specification requirement? If not, comment on possible reasons. Comment on the quality of data. $(10$ points$)$