The average fuel efficiency of U.S. light vehicles (cars, SUVs, minivans, vans, and light trucks) for 2005 was 21 miles per gallon (mpg). If the standard deviation of the population was 2.8 and the gas ratings were normally distributed, (a) what is the probability that the fuel used for a random sample of 25 light vehicles is under 18? (b) between 20 and 24?

Engineers claims that a certain formula can increase the strength, X, of concrete with mean 5000 kg/cm2 and standard deviation 120 kg/cm2 . To test the hypothesis = 5000 kg/cm2 against the alternative

a) rejected whereas the mean strength is actually 5000 kg/cm2

b) accepted whereas the mean strength is actually 4960 kg/cm2

A certain virus infects 17% of people. A test used to detect the virus in a person is positive 96% of the time if the person has the virus and 4% of the time if the person does not have the virus.

a. For a sample of 20,000 people complete the table below. The first entry has been completed for you Totals Test Result Positive Negative Has Virus . 96 x 3400 = 3264 Does Not Have Virus Totals 20,000

b. Find the probability that a person has the virus given that they have tested positive.

c. Find the probability that a person does not have the virus given that they test negative.

d. If two people are chosen at random, find the probability that at least one of them has the virus.

Three people are running for president of the student council. The polls show James has odds in favour of winning at 2:3, Rebecca has odds in favour at 7:13, and Henry has odds in favour at 1:3. Suppose that Henry withdraws and offers his support to Rebecca. Further, suppose that his supporters also switch to Rebecca. What is the probability of Rebecca winning now?

If each book in a Library has an ISBN number that begin with 2 distinct Letters followed by 5 distinct non-zero digits. What will be chance of selecting a book whose ISBN number has first leller a Consonant and last digit an odd number.

Suppose a company surveyed the work preferences and attitudes of 1,006 working adults spread over three generations: baby boomers, Generation X, and millennials. In one question, individuals were asked if they would leave their current job to make more money at another job. The sample data are summarized in the following table. Leave Job for Generation More Money? Baby Boomer Generation X Millennial Yes 124 155 166 No 202 186 173 Conduct a test of independence to determine whether interest in leaving a current job for more money is independent of employee generation. State the null and alternative hypotheses. O Ho: Interest in leaving job for more money is independent of the employee generation. Ha: Interest in leaving job for more money is not independent of the employee generation. O Ho: Interest in leaving job for more money is not independent of the employee generation. H: Interest in leaving job for more money is independent of the employee generation. O Hot Interest in leaving job for more money is not mutually exclusive of the employee generation. H : Interest in leaving job for more money is mutually exclusive of the employee generation. O Ho: Interest in leaving job for more money is mutually exclusive of the employee generation. Ha: Interest in leaving job for more money is not mutually exclusive of the employee generation. Find the value of the test statistic. (Round your answer to two decimal places.) What is the p-value? (Round your answer to four decimal places.) Using a 0.05 level of significance, what is your conclusion? O Do not reject Ho. We conclude that interest in leaving a job for more money is not independent of the employee generation. O Reject Ho. We cannot conclude that interest in leaving a job for more money is independent of the employee generation. O Do not reject Ho. We cannot conclude that interest in leaving a job for more money is independent of the employee generation. O Reject Ho. We conclude that interest in leaving a job for more money is not independent of the employee generation