STAT HOMEWORK
1.
A large collection of one-digit random numbers should have about 50% odd and 50% even digits because ve of the ten digits are odd (1, 3, 5, 7, and 9) and five are even (0, 2, 4, 6, and 8). a. Find the proportion of odd-numbered digits in the following lines from a random number table. Count carefully. 2066918922 20723Ig 40167 50420 51296 b. Does the proportion found in part a represent 6 (the sample proportion) or p (the population proportion)? c. Find the error in this estimate, the difference between 6 and p (or B - p). a. The given random number table consists of 36.67 % odd-numbered digits. (Round to two decimal places as needed.) b. Does the proportion found in part a represent 6 (the sample proportion) or p (the population proportion)? y p(the sample proportion) p (the population proportion) c. Find the error in this estimate, the difference between B and p (or E - p). Error = El% (Round to two decimal places as needed.) In a 2008 survey, people were asked their opinions on astrology-whether it was very scientific, somewhat scientific, or not at all scientific. Of 1431 who responded, 75 said astrology was very scientific. a. Find the proportion of people in the survey who believe astrology is very scientific. b. Find a 95% confidence interval for the population proportion with this belief. c. Suppose a TV news anchor said that 5% of people in the general population think astrology is very scientific. Would you say that is plausible? Explain your answer. . . . . . a. The proportion of people in the survey who believe astrology is very scientific is 0.0524 . (Round to four decimal places as needed.) b. Construct the 95% confidence interval for the population proportion with the belief that astrology is very scientific. (Round to three decimal places as needed.)On the basis of experience. a political consultant suggested that 55% of all voters in a certain area will vote for a particular party in the next provincial election. Suppose you have surveyed 20 randomly chosen people who are eligible to vote in the election, and 13 say they will vote for that party. The null hypothesis is that the proportion of all votes cast for the party in question in the next provincial election is 55%. Give the value of the test statistic that would be used to test the null hypothesis. The test statistic is z = D. (Round to two decimal places as needed.) A truelfalse test has 50 questions. Suppose a passing grade is 37 or more correct answers. Test the claim that a student knows more than half of the answers and is notjust guessing. Assume the student gets 37 answers correct out of 50. Use a signicance level of 0.05. Steps 1 and 2 of a hypothesis test procedure are given below. Show step 3, nding the test statistic and the p-value and step 4, interpreting the results. Step 1: H0: p=0.50 HA: p>0.50 Step 2: Choose the one-proportion z-test. Sample size is large enough because npo is 50(0.5) =25 and n (1 - p0) = 50(.5) = 25, and both are more than 10. Assume the sample is random. Step 3: Compute the z-test statistic and the p-value. z = D (Round to two decimal places as needed.) pvalue = D (Round to three decimal places as needed.) A manufacturer withdrew Drug V from the market after a study revealed that its use was associated with an increase in the risk of heart attack. The experiment was placebo-controlled, randomized, and double-blind. Out of 1263 people taking Drug V there were 41 heart attacks, and out of 1288 people taking the placebo, there were 29 heart attacks. Perform a hypothesis test to test whether those who take Drug V have a greater rate of heart attack than those who take a placebo. Use a level of significance of 0.10. Can we conclude that Drug V causes an increased risk of heart attack? . . . . . Determine the hypotheses for this test. Let p, represent the population proportion of heart attacks for those who take Drug V and let p2 represent the population proportion of heart attacks for those who take the placebo. Choose the correct answer below. OA. Ho: P1 P2 OF. Ho: P1 = P2 HA: P1 > P2 HA : P1 = P2 HA : P1 = P2
