Question

Consider the following results for independent random samples taken from two populations. Sample 1 Sample 2 n 1 20 n 2 40 x2 20.4 1= 22.5 S 2 4.6 s1 2.1 a. What is the point estimate of the difference between the two population means (to 1 decimal)? b. What is the degrees of freedom for the t distribution (round down your answer nearest whole number)? c. At 95% confidence, what the margin of error (to 1 decimal)? d. What is the 95% confidence interval for the difference between the two population means (to 1 decimal)? If your answer is negative value, entre minus () sign. Use z-table.

Answer 1


given n = 20 DQ=40 œ = 22:6 H2E 2014 5,= 2.2 52= 4.6. a) point estimate of the difference between the two population mean's és point estimate = že-dée E 22-5-2004 Point estimate = 2.11 b) degrees of freedom for t-distribution is - df = 0,+No:2 __ = 20+40-2 d.f. = 58 c) At 95% confidence, Mangin of Error = zt ne - aligo (2:1)? 7 64:622 20 =1.96 (0-86572 M.E. = 1.7 40

d) 95% confidence internal for the difference between the two populations mean's is CIT. E cã,-6) + 2* | sit se Vņi .nz - (22:5-20.4) + 1.961 (201)2 V20 (406)2 40 ..2:1 + 1:7 FC.T. = (0.4.3.8)|