The concentration of a certain salt in a liquid was measured in a laboratory. A random sample of 4 measurements shows a mean of 0.22 and a variance of 0.001 . A second laboratory repeats the same process with an independent sample of 5 measurements with mean 0.17 and variance 0.002 . Construct a ( 95 % ) confidence interval for estimating the difference between the populations means assuming equal variance.

The concentration of a certain salt in a liquid was measured in a laboratory. A random sample of 4 measurements shows a mean of 0.22 and a variance of 0.001 . A second laboratory repeats the same process with an independent sample of 5 measurements with mean 0.17 and variance 0.002 . Construct a 95% confidence interval for estimating the difference between the populations means assuming equal variance