2. The Air Quality Index (AQI) is used to measure air quality near roadways and industrialregions in large cities. Governments report AQI values for common pollutants to keepthe public informed about air quality. AQI values of 0-50 are regarded as good, 51-100as moderate, 101-150 as unhealthy for sensitive individuals, 151-200 as unhealthy,201-300 as very unhealthy, and beyond 300 as hazardous.The following table gives AQI values for S02 (Sulphur Dioxide) and CO (CarbonMonoxide) from a random sample of 20 locations in California, between the years 2000and 2010.Location1234567891011121314151617181920Summary StatisticsSO2 AQI14331101277304721334019₁5.6; s = 7.03CO AQI366231865168752445852512₂9.3; s = 10.42AQI Diff (SO2-CO)-2-2-31-20-8-522-9-5-7-15-23-2-5-1-2-3X=-3.7;s = 8.84 (a) Why are these data best regarded as a paired sample?(b) Do the data provide evidence that California's S02 and CO AQI leves differ pnaverage? Test at the 10% level of significance(c) Construct and interpret a 95% confidence interval for the mean difference in SO2and CO AQI levels for California.(d) Does the interval from (c) lead to a conclusion that agrees with the test from (b)?Explain why or why not.a diffonanses Do the

Given that, The two variables are AQI values for SO2 (Sulphur dioxide) and CO (Carbon Monoxide). n…

Answered: are these data best regarded as a…

MATLAB: An Introduction with Applications

6th Edition

ISBN:9781119256830

Author:Amos Gilat

Publisher:Amos Gilat

Chapter1: Starting With Matlab

Section: Chapter Questions

Problem 1P

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In a recent year, a sample of the South American Redeye Piranha was collected by fishermen on a particular river. Wildlife biologists regard this sample as a random sample of all Redeye Piranha in that river. The mean length of the 60 fish in the sample was 12.88 cm, and a 99% confidence level for the true mean length of all Redeye Piranha in that river is 12.09 cm to 13.67 cm. Explain what would happen to the length of the interval if the confidence level were decreased to 95%.
2. University researchers claim that the average enrollment at four-year colleges is higher than two-year community colleges. Two surveys are undertaken at 35 four-year universities and 35 two-year colleges. The mean enrollment at the four-year institutions was 5,466 with a standard deviation of 8,191. The average enrollment at the two-year schools was 5,068 with a standard deviation of 4,777. Using a 95% confidence level, are the findings of the surveys consistent with the university researchers’ claim? 2. Does the null hypothesis reject H0 or fail to reject H0?
The mean potassium content of a popular sports drink is listed as 132 mg in a 32-oz bottle. Analysis of 24 bottles indicates a sample mean of 131.2 mg. (a) State the hypotheses for a two-tailed test of the claimed potassium content.. a. Ho: μ= 132 mg vs. H₁: b. He: ≤132 mg vs. H₁: c. He: ≥132 mg vs. H₁: Oa Ob Oc (b) Assuming a known standard deviation of 2.1 mg, calculate the z test statistic to test the manufacturer's claim. (Round your answer to 2 decimal places. A negative value should be indicated by a minus sign.) Test statistic 132 mg >132 mg <132 mg (c) At the 2 percent level of significance (a = .02) does the sample contradict the manufacturer's claim? Decision Rule: Reject Ho
For a 4-unit class like Statistics, students should spend average of 12 hours studying for the class. A survey was done on 22 students, and the distribution of total study hours per week is bell-shaped with a mean of 12 hours and a standard deviation of 2.6 hours. Use the Empirical Rule to answer the following questions. a) 68% of the students spend between hours and hours on Statistics each week. b) 95% of the students spend between hours and hours on Statistics each week. c) 99.7% of the students spend between hours and hours on Statistics each week. Check Answer 100% 69°F Cloudy
A company that manufactures baseball bats believes that its new bat will allow players to hit the ball 30 feet farther than its current model. The owner hires a professional baseball player known for hitting home runs to hit ten balls with each bat and he measures the distance each ball is hit to test the company's claim. The results of the batting experiment are shown in the following table. Construct a 90 % confidence interval for the true difference between the mean distance hit with the new model and the mean distance hit with the older model. Assume that the variances of the two populations are the same. Let Population 1 be the distances of balls hit with the new model baseball bat and Population 2 be the distances of balls hit with the old model. Round the endpoints of the interval to one decimal place, if necessary. Hitting Distance (in Feet) New Model Old Model 215 234 202 298 224 294 211 246 215 268 248 211 255 226 228 284 247 221 214 259
2. A common claim is that garlic lowers cholesterol levels. In a test of the effectiveness of garlic, 49 subjects were treated with doses of raw garlic, and their cholesterol levels were measured before and after the treatment. The changes in their levels of LDL cholesterol have a mean of 0.4 and a standard deviation of 21. Use the sample n = 49 to construct a 95% confidence interval estimate of the mean net change in LDL cholesterol after the garlic treatment. n=49₁ x=0,4₁ 5=21₁ CL = 95%, df=n-1 df=49-1=48
In a sample of 100 steel canisters, the mean wall thickness was 8.1 mm with a standard deviation of 0.5 mm. a) Find a 95% confidence interval for the mean wall thickness of this type of canister. b) Find a 99% confidence interval for the mean wall thickness of this type of canister. c) An engineer claims that the mean thickness is between 8.02 and 8.18 mm. With what level of confidence can this statement be made? d) How many canisters must be sampled so that a 95% confidence interval will specify the mean wall thickness to within ±0.08 mm? e) How many canisters must be sampled so that a 99% confidence interval will specify the mean wall thickness to within ±0.08 mm?
A company that manufactures baseball bats believes that its new bat will allow players to hit the ball 30 feet farther than its current model. The owner hires a professional baseball player known for hitting home runs to hit ten balls with each bat and he measures the distance each ball is hit to test the company's claim. The results of the batting experiment are shown in the following table. Construct a 90 % confidence interval for the true difference between the mean distance hit with the new model and the mean distance hit with the older model. Assume that the variances of the two populations are the same. Let Population 1 be the distances of balls hit with the new model baseball bat and Population 2 be the distances of balls hit with the old model. Round the endpoints of the interval to one decimal place, if necessary. Hitting Distance (in Feet) New Model 246 240 272 262 237 250 247 235 261 216 Old Model 293 232 299 279 239 228 256 292 272 298
A researcher studying reaction time of drivers states that, "A 95% confidence interval for the mean time it takes for a driver to apply the brakes after seeing the brake lights on a vehicle in front of him is 1.2 to 1.8 seconds." What are the point estimate and margin of error for this interval? Point estimate = 1.5 seconds; margin of error = 0.95 seconds. Point estimate = 1.2 seconds; margin of error = 0.3 seconds. Point estimate = 1.5 seconds; margin of error = 0.6 seconds. Point estimate = 1.5 seconds; margin of error = 0.3 seconds. a O b O d
Suppose a recent study of Trucks and SUVs gave an average fuel efficiency of 19.2 mpg for Trucks and 21.4 mpg for SUVs. The sample standard deviation for Trucks was 3.2 mpg and 2.8 mpg for SUVs. These results were based on samples of 35 Trucks and 39 SUVs. At the 1% significance level, can we conclude that, on average, SUVs have better fuel efficiency than Trucks? Clearly state the null and alternative hypotheses, use the critical value approach (draw a detailed picture), and write out a detailed conclusion. Organize: Hypotheses: Detailed picture: Detailed conclusion:
According to the Centers for Disease Control and Prevention (CDC), the mean BMI of U.S. men of age 40–49 years old is 28.4 Using the provided sample data file, conduct a one-sample ?-z-test of a mean to test whether the mean BMI of men of age 40–49 years old who smoke daily is lower than 28.4. Conduct the ?-z-test at a significance level of ?=0.05 to test the null hypothesis, ?0:?=28.4, against the alternative hypothesis, ?1:?<28.4, where ?μ represents the mean BMI of U.S. men of age 40–49 who smoke daily. Assume that the population standard deviation of BMI, ?σ, is 8.346 The sample data provided contain BMI results collected from a 2015 survey conducted by the National Center for Health Statistics for men of age 40–49 who smoke daily. Calculate the sample mean, ?⎯⎯⎯x¯, for this data. Give your answer precise to at least one decimal place. Calculate the sample mean, ?⎯⎯⎯x¯, for this data. Give your answer precise to at least one decimal place. Compute the standard deviation, SD, of…
The summary statistics below are prices of three types of men's shoes: Dress: size = 7 ; mean = 106 and standard deviation = 73 %3D Casual: size = 5; mean = 97 and standard deviation = 23 %3D Mocassins: size = 4; mean = 73 and standard deviation =13. Can Bonferroni method be used at a 0.05 significance level to test the claim that the population means for Dress shoes and Casual shoes are significantly different? Justify your answer. 5:39 pm

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