Spell checking software catches nonword errors

8. 0.75/1 points Previous Answers MIntroStat9 4.E.508.XP. My Notes Ask Your Teacher The College Board finds that the distribution of students' SAT scores depends on the level of education their parents have. Children of parents who did not finish high school have SAT math scores X with mean 449 and standard deviation 103. Scores Y of children of parents with graduate degrees have mean 564 and standard deviation 105. Perhaps we should standardize to a common scale for equity. Find numbers a, b, c, and d such that a + bX and c + dY both have mean 500 and standard deviation 100. (Round your answers to two decimal places.) a = 64.07 b = 0.97 c = 37.14 d = 0.95 9. –/1 points MIntroStat9 4.E.509.XP. My Notes Ask Your Teacher Slot machines are now video games, with winning determined by electronic random number generators. In the old days, slot machines were like this: you pull the lever to spin three wheels; each wheel has 25 symbols, all equally likely to show when the wheel stops spinning; the three wheels are independent of each other. Suppose that the middle wheel has 12 bells among its 25 symbols, and the left and right wheels have 1 bell each. (a) You win the jackpot if all three wheels show bells. What is the probability of winning the jackpot? (Round your answer to four decimal places.) (b) What is the probability that the wheels stop with exactly 2 bells showing? (Round your answer to four decimal places.) 0.84/1 points 10. Previous Answers MIntroStat9 4.E.138. My Notes Ask Your Teacher It is difficult to conduct sample surveys on sensitive issues because many people will not answer questions if the answers might embarrass them. Randomized response is an effective way to guarantee anonymity while collecting information on topics such as student cheating or sexual behavior. Here is the idea. To ask a sample of students whether they have plagiarized a term paper while in college, have each student toss a coin in private. If the coin lands heads and they have not plagiarized, they are to answer "No." Otherwise they are to give "Yes" as their answer. Only the student knows whether the answer reflects the truth or just the coin toss, but the researchers can use a proper random sample with follow-up for nonresponse and other good sampling practices. Suppose that in fact the probability is 0.3 that a randomly chosen student has plagiarized a paper. Draw a tree diagram in which the first stage is tossing the coin and the second is the truth about plagiarism. The outcome at the end of each branch is the answer given to the randomizedresponse question. 0.5 0.7 0.35 0.15 0.5 What is the probability of a "No" answer in the randomized-response poll? 0.35 If the probability of plagiarism were 0.16, what would be the probability of a "No" response on the poll? 0.42 Now suppose that you get 37% "No" answers in a randomized-response poll of a large sample of students at your college. What do you estimate to be the percent of the population who have plagiarized a paper? % 74 11. –/1 points MIntroStat9 5.E.524.XP. My Notes Ask Your Teacher Sheila's doctor is concerned that she may suffer from gestational diabetes (high blood glucose levels during pregnancy). There is variation both in the actual glucose level and in the blood test that measures the level. A patient is classified as having gestational diabetes if the glucose level is above 140 milligrams per deciliter (mg/dl) one hour after a sugary drink is ingested. Sheila's measured glucose level one hour after ingesting the sugary drink varies according to the Normal distribution with μ = 128 mg/dl and σ = 10 mg/dl. (a) If a single glucose measurement is made, what is the probability that Sheila is diagnosed as having gestational diabetes? (Round your answer to four decimal places.) (b) If measurements are made instead on 3 separate days and the mean result is compared with the criterion 140 mg/dl, what is the probability that Sheila is diagnosed as having gestational diabetes? (Round your answer to four decimal places.) 12. –/1 points MIntroStat9 5.E.526.XP. My Notes Ask Your Teacher Here is a simple probability model for multiple-choice tests. Suppose that each student has probability p of correctly answering a question chosen at random from a universe of possible questions.