I. Based on a random sample of 3 observations, consider two competing estimators of the population mean µ: X + Xa + Xa), in = X1+;X2+ ;Xs 3 (a) Are they unbiased? (b) Which estimator is more efficient? How much more efficient? 2. Let {X1, X2, ..., Xn} be an independent random sample from Poisson(A), (a) Show that both X and S² are unbiased estimator of ). (b) Calculate the Cramer-Rao Lower Bound with respective to A. (c) Which estimator should be preferred and why?
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- In a clinical study, a random sample of 540 participants agree to have their blood drawn, which is to be examined for the presence of antibodies against a certain contagious disease. It is found in 22% of the blood samples, which experimenters hope to extrapolate to the general population. From this random sample, 10 participants' blood samples are selected at random. If X is the number of samples out of the 10 who have these antibodies, what can we say about X? A. The sample size is not large enough for us to approximate X using a normal distribution B.The expected value of X is 22 C. X can be approximated using a normal distribution in lieu of a binomial distribution D. X has a sampling distribution that is normalIf X1, X2, ... , Xn constitute a random sample of size n from an exponential population, show that X is a consis-tent estimator of the parameter θ.A simple random sample of size n= 40 is obtained from a population that is skewed left with u = 61 and o = 4.
- Suppose that X1, X2, X3, ..., X99, X100 are independent Bernoulli(1/2) random variables. What is E[(X1+X2+X3+...+X69+X70)*(X71 + X72 + ... + X99+X100)]?There are two traffic lights on a commuter's route to and from work. Let X1 be the number of lights at which the commuter must stop on his way to work, and X2 be the number of lights at which he must stop when returning from work. Suppose that these two variables are independent, each with the pmf given in the accompanying table (so X1, X2 is a random sample of size n = 2). Can you help me with 3 and 4?Let p1 and p2 be the respective proportions of women with iron-deficiency anemia in each of two developing countries. A random sample of 1900 women from the first country yielded 513 women with iron-deficiency anemia, and an independently chosen, random sample of 1700 women from the second country yielded 515 women with iron-deficiency anemia. Can we conclude, at the 0.10 level of significance, that the proportion of women with anemia in the first country is less than the proportion of women with anemia in the second country? Perform a one-tailed test. Then complete the parts below.Carry your intermediate computations to three or more decimal places and round your answers as specified in the parts below. a. State the null hypothesis H0 and the alternative hypothesis H1. b. Find the values of the test statistic. c. FInd the p-value. d. Can we conclude that the proportion of women with anemia in the first country is less than the proportion of women with anemia in the second country?
- There are two traffic lights on a commuter's route to and from work. Let X1 be the number of lights at which the commuter must stop on his way to work, and X2 be the number of lights at which he must stop when returning from work. Suppose that these two variables are independent, each with the pmf given in the accompanying table (so X1, X2 is a random sample of size n = 2). x1 0 1 2 p(x1) 0.1 0.2 0.7 ? = 1.6, ?2 = 0.44 (a) Determine the pmf of To = X1 + X2. to 0 1 2 3 4 p(to) (b) Calculate ?To. ?To = How does it relate to ?, the population mean? ?To = · ? (c) Calculate ?To2. ?To2 = How does it relate to ?2, the population variance? ?To2 = · ?2A group of high-risk automobile drivers (with three moving violations in one year) are required, according to random assignment, either to attend a traffic school or to perform supervised volunteer work. During the subsequent five-year period, these same drivers were cited for the following number of moving violations: NUMBER OF MOVING VIOLATIONS TRAFFIC SCHOOL VOLUNTEER WORK 0 26 0 7 15 4 9 1 7 1 0 14 2 6 23 10 7 8 Why might the Mann–Whitney U test be preferred to the t test for these data? Use U to test the null hypothesis at the .05 level of significance. Specify the approximate p-value for this test result.Resistors labeled as 100 Ω are purchased from two different vendors. The specification for this type of resistor is that its actual resistance be within 5% of its labeled resistance. In a sample of 180 resistors from vendor A, 150 of them met the specification. In a sample of 270 resistors purchased from vendor B, 233 of them met the specification. Vendor A is the current supplier, but if the data demonstrate convincingly that a greater proportion of the resistors from vendor B meet the specification, a change will be made. a) State the appropriate null and alternate hypotheses. b) Find the P-value. c) Should a change be made?
- Suppose that Fred, a United States politician from a large western state, wants to create a new law that would require children under the age of 16 to be accompanied by an adult at all times in public places. Based on previous voting records, Fred believes that he could gain the support of 2525% of likely voters. To test his hypothesis, Fred conducts a random survey of 12001200 likely voters and asks if they would support his proposition. Let ?X denote the number of likely voters in Fred's sample that pledge their support, assuming that Fred's belief that 25%25% of likely voters would support his proposal. Which of the following statements are true about the sampling distribution of ?X? -The sampling distribution of ?X is approximately binomial with ?=1200n=1200 and ?=0.25p=0.25. -The sampling distribution of ?X is exactly normal with ?=0.5μ=0.5 and ?=0.0125σ=0.0125. -The sampling distribution of ?X is exactly binomial with ?=1200n=1200 and ?=0.25p=0.25. -The sampling…Chapter 6, Section 5, Exercise 236 Use a t-distribution and the given matched pair sample results to complete the test of the given hypotheses. Assume the results come from random samples, and if the sample sizes are small, assume the underlying distribution of the differences is relatively normal. Assume that differences are computed using d=x1-x2.Test H0 : μd=0 vs Ha : μd≠0 using the paired difference sample results x¯d=10.51, sd=11.6, nd=25. Give the test statistic and the p-value.Round your answer for the test statistic to two decimal places and your answer for the p-value to three decimal places.test statistic = Enter your answer; test statisticp-value = Enter your answer; p-value Give the conclusion using a 5% significance level. Reject H0. Do not reject H0.Consider the following population model for household consumption: cons = a + b1 * inc+ b2 * educ+ b3 * hhsize + u where cons is consumption, inc is income, educ is the education level of household head, hhsize is the size of a household. Suppose that the variable for consumption is measured with error, so conss = cons + e, where conss is the mismeaured variable, cons is the true variable, e is random, i.e., e is independent of all the regressors. What would we expect and why? A) OLS estimators for the coefficients will all be biased B) OLS estimators for the coefficients will all be unbiased C) ALL the standard errors will be bigger than they would be without the measurement error D) both B and C