Let x be a random variable representing dividend yleld of bank stocks. We may assume that x has a normal distribution with a = 3.1%. A random sample of 10 bank stocks gave the following yields (in percents). 5.7 4.8 6.0 4.9 4.0 3.4 6.5 7.1 5.3 6.1 The sample mean is x= 5.38%. Suppose that for the entire stock market, the mean dividend vield is u= 4.7%. Do these data Indicate that the dividend yield of all bank stocks is higher than 4.7%? Use a = 0.01. (a) What is the level of significance? State the null and alternate hypotheses. Will you use a left-tailed, right-tailled, or two-taled test? O Ho: H = 4.7%; H: u < 4.7%; left-tailed O Ho: H > 4.7%; H1: µ = 4.7%; right-tailed O Ho: H = 4.7%; H;: µ > 4.7%; right-tailed O Ho: H = 4.7%; H: H* 4.7%; two-tailed (b) What sampling distribution will you use? Explain the rationale for your choice of sampling distribution. O The standard normal, since we assume that x has a normal distribution with known o. O The Student's t, since n is large with unknown o. The standard normal, since we assume that x has a normal distribution with unknown a. O The Student's t, since we assume that x has a normal distribution with known a. Compute the z value of the sample test statistic. (Round your answer to two decimal places.) (c) Find (or estimate) the P-value. (Round your answer to four decimal places.)

Suppose a professor uses a normal distribution to assign grades in her math class. • She assigns an A to students scoring more than 1.9 standard deviations above the mean. • She assigns an F to students scoring more than 2.2 standard deviations below the mean. She assigns a B to students who Score between 1 and 1.9 standard deviations above the mean. • She assigns a D to students who Score between 1.2 and 2.2 standard deviations below the mean. • All other students get a C. Use the Cumulative Z-Score Table to answer the following questions. The Z-Score Table can be found below by selecting "Read". Write your answer as a percent using 2 decimal places. What percent of the class receives each grade assuming the scores are normally distributed? Hint % will recieve an A % will recieve a B % will recieve a C % will recieve a D % will recieve an F

The Office of Student Services at a large western state university maintains information on the study habits of its full-time students. Their studies indicate that the mean amount of time undergraduate students study per week is 20 hours. The hours studied follows the normal distribution with a population standard deviation of 12 hours. Suppose we select a random sample of 100 current students. What is the standard error of the mean? 1.20 12 .95 2.70

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Assume all populations are normally distributed. A travel analyst claims that the mean price of a round trip flight from New York City to Los Angeles is less than $507. In a random sample of 55 round trip flights from NYC to LA, the mean price is $502. Assume the population standard deviation is $111. At α = 0.05, is there enough evidence to support the travel analyst’s claim?

A magazine claims that the mean amount spent by a customer at Burger Stop is greater than the mean amount spent by a customer at Fry World. The results for samples of customer transactions for the two fast food restaurants are shown below. At x = 0.01, can you support the magazine's claim? Assume the population variances are equal. Assume the samples are random and independent, and the populations are normally distributed. Complete parts (a) through (e) below. Burger Stop Fry World X₁ = $11.22 X₂ = $10.59 $₁ = $0.79 $2 = $0.64 n₂ = 10 n₁ = 12 (a) Identify the claim and state Ho and H₂. Which is the correct claim below? O A. "The mean amount spent by a customer at Burger Stop is greater than the mean amount spent by a customer at Fry World." OB. "The mean amount spent by a customer at Burger Stop is equal to the mean amount spent by a customer at Fry World." O c. "The mean amount spent by a customer at Burger Stop is not equal to the mean amount spent by a customer at Fry World." O D.…