Independent random samples were selected from populations 1 and 2. The sample sizes, means, and variances are as follows.

		Population
		1	2
Sample Size		100	100
Sample Mean		5.0	2.5
Sample Variance		1.6	0.8

a. Find a point estimate for the difference in the two population means. (Use _{1 2}. ₁is the mean of Population 1 and₂is the mean of Population 2.)

b. Find a 90% confidence interval for the difference in the population means. (Use _{1 2} .Round your answers to three decimal places.)

Suppose water samples from 100rainfalls are analyzed for pH, andxandsof pH from the 100 water samplesare equal to3.5and0.7, respectively. Find a 99% confidence interval for the mean pH in rainfall. (Round your answers to two decimal places.)(