Electronic devices contain electric circuits etched into wafers made of silicon. These silicon wafers are sealed with an ultrathin layer of silicon dioxide, in a process known as oxidation. This can be done with either new or recycled wafers.
In a study described in the book Statistical Case Studies for Industrial Process Improvement by V. Czitrom and P. Spagon, both new and recycled wafers were oxidized, and the thicknesses of the layers were measured to determine whether they tended to differ between the two types of wafers. Recycled wafers are cheaper than new wafer, so the hope was that they would perform at least as well as the new wafers. Following are 36 thickness measurements (in tenth s of a nanometer) for both new and recycled wafers.
Suppose that it is desired to use the type of wafer whose distribution has less spread. Write a brief paragraph that explains which type of wafer to use and why. Which measure is more useful for spread in this case, the standard deviation or the
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- Researchers interested in lead exposure due to car exhaust sampled the blood of 52 police officers subjected to constant inhalation of automobile exhaust fumes while working traffic enforcement in a primarily urban environment. The blood samples of these officers had an average lead concentration of 124.32 µg/l and a SD of 37.74 µg/l; a previous study of individuals from a nearby suburb, with no history of exposure, found an average blood level concentration of 35 µg/l. Based on your preceding result, without performing a calculation, would a 99% confidence interval for the average blood concentration level of police officers contain 35 µg/l? Based on your preceding result, without performing a calculation, would a 99% confidence interval for this difference contain 0? Explain why or why not.arrow_forwardThe performance of two analysts in determining total mercury (mg / kg) in fish was evaluated using the absorption spectrometry method. The results on the concentrations of mercury found in fish, for each analyst, are presented in the table below: Analyst 1 Analyst 2 7 12 9 8 6 9 11 13 13 14 8 9 7 8 13 10 12 7 9 15 (a)Is the performance in determining total mercury for Analyst 1 more accurate than Analyst 2? Compare the accuracy in the results of the two analysts at a 95% confidence level. Explain. (b)Are the results obtained by the two analysts, in the concentrations of mercury found in the fish, statistically equivalent, with 95% confidence? Explainarrow_forwardPeriodically, the county Water Department tests the drinking water of homeowners for contaminants such as lead and copper. The lead and copper levels in water specimens collected in 1998 for a sample of 10 residents of a subdevelopement of the county are shown below. lead (μμg/L) copper (mg/L) 4.44.4 0.6430.643 2.42.4 0.570.57 1.51.5 0.460.46 2.62.6 0.8950.895 5.95.9 0.20.2 3.43.4 0.540.54 3.83.8 0.2450.245 1.61.6 0.5830.583 5.75.7 0.7690.769 1.71.7 0.2150.215 (a) Construct a 9999% confidence interval for the mean lead level in water specimans of the subdevelopment. ≤μ≤≤μ≤ (b) Construct a 9999% confidence interval for the mean copper level in water specimans of the subdevelopment. ≤μ≤≤μ≤arrow_forward
- Analysis of several plant-food preparations for potassium ion yielded the following data:arrow_forwardCompare the two separate scatterplots. In particular, how do the associtation compare between women with pets vs. women without pets? Does one group have more variation in systolic blood pressure than the other? If so, for which group? Does systolic blood pressure seem higher for common ages between the two groups? If so, for which group?arrow_forwardPeriodically, the county Water Department tests the drinking water of homeowners for contminants such as lead and copper. The lead and copper levels in water specimens collected in 1998 for a sample of 10 residents of a subdevelopement of the county are shown below. lead (μμg/L) copper (mg/L) 4.44.4 0.4840.484 2.72.7 0.0760.076 5.35.3 0.5950.595 3.33.3 0.1280.128 5.55.5 0.4690.469 1.71.7 0.4060.406 0.40.4 0.8480.848 0.70.7 0.0220.022 44 0.860.86 2.82.8 0.4250.425 (a) Construct a 99% confidence interval for the mean lead level in water specimans of the subdevelopment. blank≤μ≤blank (b) Construct a 99% confidence interval for the mean copper level in water specimans of the subdevelopment. blank≤μ≤blankarrow_forward
- Life-saving drug: Penicillin is produced by the Penicillin fungus, which is grown in a broth whose sugar content must be carefully controlled. Several samples of broth were taken on three successive days, and the amount of dissolved sugars, in milligrams per milliliter, was measured on each sample. The results were as follows. Day 1: 5.2 5.0 5.4 5.2 5.3 5.0 4.9 5.0 5.2 5.0 4.6 5.3 Day 2: 5.6 4.8 4.9 5.3 5.2 4.9 5.4 5.0 5.4 4.9 5.5 5.4 Day 3: 5.9 4.9 5.3 5.4 5.2 5.5 5.0 5.8 5.5 5.4 5.4 5.1 Construct an ANOVA table. Round your answers to four decimal places as needed. One-way ANOVA: Sugar Concentration Source DF SS MS F P Days Error Totalarrow_forwardConsider the following: In general, when people diet they typically lose 10 lbs. (?σ = 2). A random sample of 16 people on the keto diet lost 15 lbs. Do people on the keto diet lose more or less weight than people on diets in general? 4. What is the research hypothesis? a) Weight loss in the keto diet sample does not differ from weight loss in the population of dieters in general (H1: X-bar = Mu) b)Weight loss in the keto diet sample does differ from weight loss in the population of dieters in general (H1: X-bar = Mu) c) Weight loss in the keto diet sample does not differ from weight loss in the population of dieters in general (H1: X-bar does not equal Mu) d) Weight loss in the keto diet sample does differ from weight loss in the population of dieters in general (H1: X-bar does not equal Mu)arrow_forwardA paper investigated the driving behavior of teenagers by observing their vehicles as they left a high school parking lot and then again at a site approximately 1 2 mile from the school. Assume that it is reasonable to regard the teen drivers in this study as representative of the population of teen drivers. Amount by Which Speed Limit Was Exceeded MaleDriver FemaleDriver 1.2 -0.1 1.4 0.4 0.9 1.1 2.1 0.7 0.7 1.1 1.3 1.2 3 0.1 1.3 0.9 0.6 0.5 2.1 0.5 (a) Use a .01 level of significance for any hypothesis tests. Data consistent with summary quantities appearing in the paper are given in the table. The measurements represent the difference between the observed vehicle speed and the posted speed limit (in miles per hour) for a sample of male teenage drivers and a sample of female teenage drivers. (Use μmales − μfemales.Round your test statistic to two decimal places. Round your degrees of freedom down to the nearest whole number. Round your p-value to…arrow_forward
- Kaitlyn measures the upload speed in megabits per second of her home broadband internet connection during peak hours and off-peak hours. The results are provided in the accompanying table. Peak Off-Peak 5.83 5.14 6.05 6.80 7.14 6.98 3.54 5.77 5.45 7.27 5.90 6.62 5.81 6.19 4.82 6.08 6.37 6.59 4.65 5.58 5.30 7.41 6.48 6.26 5.96 6.37 5.79 6.31 6.84 6.55 5.06 4.95 5.61 7.03 6.45 6.77 Examine the results of Kaitlyn's test to determine the statements that compare the medians and interquartile ranges of the data sets to each other in terms of this situation. Select the two correct answers. The median upload speed during peak hours is 5.905 megabits per second, which is less than the median upload speed during off-peak hours, 7.005 megabits per second. The upload speeds during peak hours are slower on average compared to off-peak times. The median upload speed during peak hours is 6.37 megabits per second, which is greater than the median upload speed during…arrow_forwardPeriodically, the county Water Department tests the drinking water of homeowners for contaminants such as lead and copper. The lead and copper levels in water specimens collected in 1998 for a sample of 10 residents of a subdevelopement of the county are shown below. lead (μμg/L) copper (mg/L) 4.4 0.643 2.4 0.57 1.5 0.46 2.6 0.895 5.9 0.2 3.4 0.54 3.8 0.245 1.6 0.583 5.7 0.769 1.7 0.215 (a) Construct a 9999% confidence interval for the mean lead level in water specimans of the subdevelopment. ≤μ≤arrow_forwardA paper investigated the driving behavior of teenagers by observing their vehicles as they left a high school parking lot and then again at a site approximately 1 2 mile from the school. Assume that it is reasonable to regard the teen drivers in this study as representative of the population of teen drivers. Amount by Which Speed Limit Was Exceeded MaleDriver FemaleDriver 1.3 -0.1 1.3 0.4 0.9 1.1 2.1 0.7 0.7 1.1 1.3 1.2 3 0.1 1.3 0.9 0.6 0.5 2.1 0.5 (a) Use a .01 level of significance for any hypothesis tests. Data consistent with summary quantities appearing in the paper are given in the table. The measurements represent the difference between the observed vehicle speed and the posted speed limit (in miles per hour) for a sample of male teenage drivers and a sample of female teenage drivers. (Use μmales − μfemales.Round your test statistic to two decimal places. Round your degrees of freedom down to the nearest whole number. Round your p-value to…arrow_forward
- Glencoe Algebra 1, Student Edition, 9780079039897...AlgebraISBN:9780079039897Author:CarterPublisher:McGraw Hill