Solar energy generation along highways. Refer to the International Journal of Energy and Environmental Engineering (December 2013) study of solar energy generation along highways, Exercise 8.39 (p. 457). Recall that the researchers compared the mean monthly amount of solar energy generated by east-west- and north-south-oriented solar panels using a matched-pairs experiment. However, a small sample of only five months was used for the analysis. How many more months would need to be selected to estimate the difference in means to within 25 kilowatt-hours with a 90% confidence interval? Use the information provided in the SOLAR file to find an estimate of the standard error required to carry out the calculation.
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Statistics for Business and Economics (13th Edition)
- 1) A series of experiments were conducted to determine the effect of air voids on percentage retained strength of asphalt. For purposes of the experiment, air voids are controlled at three levels; low (1-3%), medium (4-6%), and high (7-9%). The data are shown in Table 1. Do the different levels of air voids significantly affect mean retained strength? Use a = 0.05. Table 1: Results of the air voids effect on percentage retained strength of asphalt Air Voids Low Medium High 106 80 78 90 69 80 Retained Strength (%) 103 94 62 90 91 69 79 70 76 88 83 85 92 87 69 95 83 85arrow_forwardExercise 2. A study is designed to test whether there is a difference in mean daily calcium intake in adults with normal bone density and adults with osteoporosis. Adults 60 years of age with normal bone density and osteoporosis are selected at random from hospital records and invited to participate in the study. Each participant's daily calcium intake (mg) is measured based on reported food intake and supplements. The data are shown below. Normal Bone Density: 1200 1000 980 900 750 800 Osteoporosis: 890 650 1100 900 400 350 480 Do these data give statistical evidence of differences in mean calcium intake across the two groups? That is, do these data give statistical evidence that the process means, say mean(Y:RE,) and mean(Y:RE2) are different? Here, Y = daily calcium intake (mg), RE, = "Nature generates a 60-year-old with normal bone density" and RE2 ="Nature generates a 60-year-old with osteoporosis." (a) Carefully describe the target of inference. Hint: This will be a difference bw…arrow_forwardPlease use the accompanying Excel data set or accompanying Text file data set when completing the following exercise. Cloud seeding has been studied for many decades as a weather modification procedure (for an interesting study of this subject, see the article in Technometrics, "A Bayesian Analysis of a Multiplicative Treatment Effect in Weather Modification", Vol. 17, pp. 161-166). The rainfall in acre-feet from 20 clouds that were selected at random and seeded with silver nitrate follows: 17.0, 29.7, 18.8, 26.1, 21.3, 17.8, 30.8, 22.4, 20.2, 26.9. 30.9, 26.1, 24.0, 23.7, 25.9. 20.8, 28.2, 33.8, 25.7, 30.6 (a) Can you support a claim that mean rainfall from seeded clouds exceeds 24.0 acre-feet? Use a = 0.01. There is V evidence to indicate that the true mean rainfall is greater than 24.0 acre-feet at a = 0.01. (b) Compute the power of the test if the true mean rainfall is 26.0 acre-feet. i Round your answer to one decimal place (e.g. 98.7). (c) What sample size would be required to…arrow_forward
- 5. An ecologist is studying the flower Iris versicolor. He measures the width and length of 100 petals of this flower from a large collection of specimens and obtains the following data. Width: AVG = 1.3 cm, SD = 0.2 cm Length: AVG = 4.3 cm, SD = 0.5 cm r = 0.65 One of the petals is at the 30th percentile of both width and length. Relative to all the petals at the 30th percentile width, this petal's length is (circle one) smaller than average about average larger than average Justify your answer using a written explanation and/or a diagram.arrow_forwardEvaluate the source for reputability, transparency, andbeing evidential. Scenario: In a study conducted by the Pew Research Center, 681 university students were surveyed. Of those surveyed, 32% reported experiencing food insecurity - and going without food to pay for textbooks and housing instead. Short answer A. The exact question reads "Within the last 30 days, have you gone without food to pay for textbooks or housing instead?": describe the type of data collected by this question as precisely as possible. B.University administrators were expecting a proportion closer to 9%. Without resortingto any analysis methods, does it appear that the result has statistical significance?arrow_forwardAccording to the World Bank’s year 2015 estimates of the Poverty Overview, 10% of the world population lived on less than US $1.90 a day. Angela, a development economist, wants to conduct a comparative study in her local community of the Bronx, New York. She randomly selects 200 individuals from the Bronx and finds that 0% of the sample is living below $1.90 a day. Using this information, clearly identify the parameter and statistic. Using this information, the parameter is ______ and statistic is _______ respectively. Select one: a. 10%, 200 b. $1.90, 200 c. 10%, 0% d. 0%, 10%arrow_forward
- Seven different hardwood concentrations are being studied to determine their effect on the strength of the paper produced. However, the pilot plant can only produce three runs each day. As days may differ, the analyst uses the balanced incomplete block design that follows. Analyze the data from this experiment (use a = 0.05) and draw conclusions. Hardwood Days Concentration (%) 1 2 3 4 5 6. 7 2 114 120 117 4 126 120 119 137 117 134 141 129 149 10 145 150 143 12 120 118 123 14 136 130 127arrow_forwardJoan's Nursery specializes in custom-designed landscaping for residential areas. The estimated labor cost associated with a particular landscaping proposal is based on the number of plantings of trees, shrubs, and so on to be used for the project. For cost estimating purposes, managers use one and half hours of labor time for the planting of a medium-sized tree. Actual times from a sample of 10 plantings during the past month follow (times in hours). 2.3 0.9 2.1 1.4 3.2 2.4 2.1 1.8 3.3 1.4 With a 0.05 level of significance, test to see whether the mean tree-planting time differs from one and half hours. a. State the null and alternative hypotheses. H0 : =u 1.5 Ha : not=u 1.5 b. Compute the sample mean. (to 1 decimal) c. Compute the sample standard deviation. (to 3 decimals) d. What is the p-value? t-value (to 3 decimals) p-value e. What is your conclusion? We reject the null. There enough evidence to prove that the mean tree-planting time differs from hoursarrow_forwardA test was conducted of two overnight mail delivery services. Two samples of identical deliveries were set up so that both delivery services were notified of the need for a delivery at the same time. The hours required to make each delivery follow. Do the data shown suggest a difference in the delivery times for the two services? Use a .05 le of significance for the test. Use Table 1 of Appendix B. Click on the datafile logo to reference the data. DATA file Service Delivery 1 2 24.5 26.0 28.0 21.0 18.0 36.0 25.0 21.0 24.0 26.0 31.0 28.0 25.5 32.0 20.0 19.5 28.0 29.0 22.0 23.5 29.5 30.0 3 4 6. 9. 10 11 What is the z-statistic? If required, round your answer to two decimal places. Enter negative values as negative number, if necessary. .30 What is the p-value? If required, round your answer to two decimal places. .7642 Conclude:arrow_forward
- Tourism is extremely important to the economy of Florida. Hotel occupancy is an often-reported measure of visitor volume and visitor activity (Orlando Sentinel, May 19, 2018). Hotel occupancy data for February in two consecutive years are as follows. Current Year 1,394 1,700 Occupied Rooms Total Rooms a. Formulate the hypothesis test that can be used to determine whether there has been an increase in the proportion of rooms occupied over the one-year period. Let p₁ = population proportion of rooms occupied for current year P2 = population proportion of rooms occupied for previous year 0.82 Previous Year 1,404 1,800 Ho: P1 P2 less than or equal to 0 Ha P₁ P2 greater than 0 b. What is the estimated proportion of hotel rooms occupied each year (to 2 decimals)? Current year Previous Year c. Conduct a hypothesis test. What is the p-value (to 4 decimals)? Use Table 1 from Appendix B. 0.78arrow_forward4arrow_forwardIf the data set of measurements was entered in an Excel spreadsheet in cells A1 through E14, what formuls will you enter in a blank cell to calculate the number of samples in that data set?arrow_forward
- Glencoe Algebra 1, Student Edition, 9780079039897...AlgebraISBN:9780079039897Author:CarterPublisher:McGraw HillBig Ideas Math A Bridge To Success Algebra 1: Stu...AlgebraISBN:9781680331141Author:HOUGHTON MIFFLIN HARCOURTPublisher:Houghton Mifflin Harcourt