A molecular biologist is studying the effectiveness of a particular enzyme to digest a certain sequence of DNA nucleotides. He divides six DNA samples into two parts, treats one part with the enzyme, and leaves the other part untreated. He then uses a polymerase chain reaction assay to count the number of DNA fragments that contain the given sequence. Another molecular biologist repeats the study with a different design. She makes up 12 DNA samples, and then chooses 6 at random to be treated with the enzyme and 6 to remain untreated. The results are as follows: Enzyme present: 12 15 14 22 2220 Enzyme absent: 23 39 37 18 26 23 Let μx represent the population mean with the enzyme absent and let μy represent the population mean with the enzyme present. Find a 95% confidence interval for the difference μ✗- My (Round the final answers to three decimal places.)

This is not the correct solution. Is there another solution avaliable for this problem?

The average salary for a civil engineering major is $75,000 with a standard deviation of $10,000. A university wants to determine how well their students in their civil engineering program get paid after graduating. They ask one class of 80 students in a course to give their salaries after graduating. What is the probability the average salary of the 80 students is between $73,000 and $77,000? 0.16 O 0.93 O 0.68 O 0.78

A survey of the white and nonwhite population in a local area reveals the following annual trip frequencies to the nearest state park:  X̄1 = 4.1  X̄2= 3.1  s21 = 14.3  s22= 12.0  N1= 20  N2= 16  Where the subscript '1' denotes the white population and the dubscript '2' denotes the nonwhite population. Please solve (d) and (e) as a-c have been solved in the previous question.  (a) assume the variances are equal, and test the null hypothesis that there is no difference between the park-going frequences of whites and nonwhites (b) repeat the exercise, assuming that the variances are unequal  (c) Find the p-value associated with the tests in parts (a) and (b)  (d) Associated with the test in part (a), find a 95% confidence interval for the difference in means  (e) repeat parts a-d, assuming sample sizes of n1= 24 and n2= 12