To construct a 95% confidence interval estimate for the difference in the average resistance between regular and alloyed wires, a random sample of 14 regular wires yielded a mean of 0.136 ohm and a standard deviation of 0.004 ohms, and a random sample of 17 alloyed wires yielded a mean of 0.083 ohm and a standard deviation of 0.005 ohm. Assume that the population variances are equal.
a. What additional assumption is needed to proceed with statistical inference about the means?
b. (10pts = 1 2 4 1 2 1). Based on these sample data, construct and interpret the 95% confidence interval by finding the following:
1) The point estimate.
2) The critical value
3) The standard error.
4) The margin of error.
5) The lower and upper limit of the 95 % confidence interval.
6) Interpret the confidence interval you obtained in part (b5) above.