Coffee beans: Refer to Exercise 12. A test of the hypotheses
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Elementary Statistics ( 3rd International Edition ) Isbn:9781260092561
- Unfortunately, arsenic occurs naturally in some ground water.t A mean arsenic level of u = 8.0 parts per billion (ppb) is considered safe for agricultural use. A well in Texas is used to water cotton crops. This well is tested on a regular basis for arsenic. A random sample of 36 tests gave a sample mean of x = 7.1 ppb arsenic, with s = 2.2 ppb. Does this information indicate that the mean level of arsenic in this well is less than 8 ppb? Use a = 0.01. A USE SALT (a) What is the level of significance? State the null and alternate hypotheses. O Ho: H= 8 ppb; H,: H > 8 ppb O Ho: H 8 ppb; H: H = 8 ppb (b) What sampling distribution will you use? Explain the rationale for your choice of sampling distribution. O The standard normal, since the sample size is large and a is unknown. O The Student's t, since the sample size is large and a is known. O The standard normal, since the sample size is large and a is known. O The Student's t, since the sample size is large and a is unknown. What is…arrow_forwardThe data in NutritionStudy include information on nutrition and health habits of a sample of 315 people. One of the variables is VitaminUse, indicating whether a person takes a multivitamin pill regularly or occasionally or not at all. Use technology to test whether the data provide evidence that the proportion taking a vitamin pill regularly is different from 35 % given. Clearly state the null and alternative hypotheses. : : 42 : Pi : P2 :: 0.35 : 2 :: P1 : p2 :: :: r Ho: vs Hg: ::arrow_forwardGiven the null and alternative hypotheses, sample means, sample sizes, and population standard deviations shown to the right, conduct a hypothesis H, H.- O B. z> O C. z< Calculate the value of the test statistic. z= (Round to two decimal places as needed.) Vevidence conclude that the mean of population 1 is less than the mean of population 2 Since the test statistic V in the rejection region, V the null hypothesis. There isarrow_forward
- The annual rainfall in a certain region is modeled using the normal distribution shown below. The mean of the distribution is 34.1 cm and the standard deviation is 3.4 cm. In the figure, V is a number along the axis and is under the highest part of the curve. And, U and W are numbers along the axis that are each the same distance away from V. Use the empirical rule to choose the best value for the percentage of the area under the curve that is shaded, and find the values of U, V, and W. Percentage of total area shaded: (Choose one) V 25 30 35 40 45 ( cm)arrow_forwardA random sample of size n = 19 observations was drawn from a normal population with variance o? = 3.1. The sample mean was = 22.5. The researcher's interest was to defend that the population mean u > 25. What is the critical region (aka rejection region) for the test a = 0.05? Drawing a picture may be helpful. Draw your conclusion. Calculate the power of the test when the alternative value for u = 27.arrow_forwardThe annual rainfall in a certain region is modeled using the normal distribution shown below. The mean of the distribution is 36.5 cm and the standard deviation is 5.2 cm. In the figure, V is a number along the axis and is under the highest part of the curve. And, U and W are numbers along the axis that are each the same distance away from V. Use the empirical rule to choose the best value for the percentage of the area under the curve that is shaded, and find the values of U, V, and W. Percentage of total area shaded: (Choose one) ▼ 200 35 | 55 25 30 40 45 50 ( cm) Submit Continue |Privacy Center © 2022 McGraw Hill LLC. All Rights Reserved. Terms of Use DIl S0 FB F7 esc F3arrow_forward
- The average wind speed in Casper Wyoming has been found to 12.7 miles per hour and in Phoenix Arizona it is 6.2 mph. To test the relationship between the averages, the average wind speed has calculated for a sample of 31 days for each city. The results are reported below. Is there sufficient evidence at alpha = 0.05 to conclude that the average wind speed is greater in Casper or Phoenix ? Sample size Casper 31 Phoneix 31 Sample mean 12.85mph 7.9mph Sample standard deviation 3.3mph 2.8mpharrow_forwardEstimate the P-value for a test of H0: μ = 500 versus H1: μ < 500 with test value t = -1.738 and a sample size of 18.arrow_forwardThe annual rainfall in a certain region is modeled using the normal distribution shown below. The mean of the distribution is 41.8 cm and the standard deviation is 5.3 cm. In the figure, V is a number along the axis and is under the highest part of the curve. And, U and W are numbers along the axis that are each the same distance away from V. Use the empirical rule to choose the best value for the percentage of the area under the curve that is shaded, and find the values of U, V, and W. Percentage of total area shaded: (Choose one) 25 30 35 40| 45 50 55 60 ( cm)arrow_forward
- The annual rainfall in a certain region is modeled using the normal distribution shown below. The mean of the distribution is 36.9 cm and the standard deviation is 4.8 cm. In the figure, V is a number along the axis and is under the highest part of the curve. And, U and W are numbers along the axis that are each the same distance away from V. Use the empirical rule to choose the best value for the percentage of the area under the curve that is shaded, and find the values of U, V, and W. Percentage of total area shaded: (Choos 20 25 30 35 0 40 0 45 50 55 ( cm) Check Save For Later Submit 2021 McGraw Hill LLC. A Rights Reserved. Terms of Use | Privacy Center MacBook 80 F3 88 F4 44 esc F1 F10 FS FB F9 @ 23 $ & 3 5 6 7 8 9 Q E T. Y P A F G H K ock C V alt alt MOSISO command optic ontrol option commandarrow_forwardThe personality trait of "Conscientiousness" (someone who is organized, responsible, and can control their impulses) has μ = 120 and σ =9. Test whether ARC students (n = 9, M = 126) differ on Conscientiousness. α = .05. zM (z score for the sample mean) =arrow_forwardThe corrosive effects of various soils on coated and uncoated steel pipe was tested by using a dependent sampling plan. The data collected are summarized below, where d is the amount of corrosion on the coated portion subtracted from the amount of corrosion on the uncoated portion. Does this random sample provide sufficient reason to conclude that the coating is beneficial? Use a = 0.01 and assume normality. n- 40, Σd- 207, Σα? = 6199 (a) Find t. (Give your answer correct to two decimal places.) (ii) Find the p-value. (Give your answer correct to four decimal places.) (b) State the appropriate conclusion. O Reject the null hypothesis, there is significant evidence that the coating is beneficial. Reject the null hypothesis, there is not significant evidence that the coating is beneficial. Fail to reject the null hypothesis, there is significant evidence that the coating is beneficial. Fail to reject the null hypothesis, there is not significant evidence that the coating is beneficial.arrow_forward
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