Question

A 99% CI on the difference between means will be (longer than/wider than/the same length as/shorter than/narrower than )a 95% CI on the difference between means.

In semiconductor manufacturing, wet chemical etching is often used to remove silicon from the backs of wafers prior to metalization. The etch rate is an important characteristic in this process and known to follow a normal distribution. Two different etching solutions have been compared, using two random samples of 10 wafers for each solution. Assume the variances are equal. The etch rates are as follows (in mils per minute):

Solution 1			Solution 2
9.8	10.2		10.6	10.4
9.4	10.3		10.6	10.2
9.3	10.0		10.7	10.7
9.6	10.3		10.4	10.4
10.2	10.1		10.5	10.3

(a) Calculate the sample mean for solution 1: x¯1=  Round your answer to two decimal places (e.g. 98.76).

(b) Calculate the sample standard deviation for solution 1: s₁ =  Round your answer to three decimal places (e.g. 98.765).

(c) Calculate the sample mean for solution 2: x¯2=  Round your answer to two decimal places (e.g. 98.76).

(d) Calculate the sample standard deviation for solution 2: s₁ =  Round your answer to three decimal places

(e) Test the hypothesis H0:μ1=μ2 vs H1:μ1≠μ2.
Calculate t₀ =  Round your answer to two decimal places (e.g. 98.76).

(f) Do the data support the claim that the mean etch rate is different for the two solutions? Use α=0.05.                            yesno

(g) Calculate a 95% two-sided confidence interval on the difference in mean etch rate.

(Calculate using the following order: x¯1-x¯2)
(   ≤ μ1-μ2 ≤  ) Round your answers to three decimal places (e.g. 98.765).

Answer 1