Concept explainers
In west Texas, water is extremely important. The following data represent pH levels in ground water for a random sample of 102 west Texas wells. A pH less than 7 is acidic and a pH above 7 is alkaline. Scanning the data, you can see that water in this region tends to be hard (alkaline). Too high a pH means the water is unusable or needs expensive treatment to make it usable (Reference: C. E. Nichols and V. E. Kane, Union Carbide Technical Report K/UR-1).
These data are also available for download at the Companion Sites for this text. For convenience, the data are presented in increasing order.
Compute a 75% Chebyshev interval centered on the mean.
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- In a survey of 2727 adults, 1463 say they have started paying bills online in the last year. Construct a 99% confidence interval for the population proportion. Interpret the results. A 99% confidence interval for the population proportion is (Round to three decimal places as needed.) Interpret your results. Choose the correct answer below. (D). A. With 99% confidence, it can be said that the population proportion of adults who say they have started paying bills online in the last year is between the endpoints of the given confidence interval. B. With 99% confidence, it can be said that the sample proportion of adults who say they have started paying bills online in the last year is between the endpoints of the given confidence interval. ○ C. The endpoints of the given confidence interval show that adults pay bills online 99% of the time.arrow_forwardA research center claims that at least 28% of adults in a certain country think that their taxes will be audited. In a random sample of 600 adults in that country in a recent year, 25% say they are concerned that their taxes will be audited. At a = 0.10, is there enough evidence to reject the center's claim? Complete parts (a) through (d) below. ... (a) Identify the claim and state Ho and Ha. Identify the claim in this scenario. Select the correct choice below and fill in the answer box to complete your choice. (Type an integer or a decimal. Do not round.) A. At least B. Less than % of adults in the country think that their taxes will be audited. % of adults in the country think that their taxes will be audited. C. The percentage of adults in the country who think that their taxes will be audited is not %. D. % of adults in the country think that their taxes will be audited. Let p be the population proportion of successes, where a success is an adult in the country who thinks that…arrow_forwardThe table shows the total square footage (in billions) of retailing space at shopping centers and their sales (in billions of dollars) for 10 years. Construct a 90% prediction interval for sales when the total square footage is 5.7 billion. The equation of the regression line is y = 567.939x - 1985.560. Total 4.9 5.2 5.3 5.4 5.5 5.6 5.9 5.9 5.9 6.1 Square Footage, x Sales, y 880.1 935.5 989.5 1056.9 1100.7 1201.9 1283.4 1346.3 1434.8 1549.5 Click the icon to view a table of critical values for the t-distribution. Construct a 90% prediction interval for the sales when the total square footage is 5.7 billion. Choose the correct prediction interval below, rounded to the nearest million dollars.arrow_forwardThe maximum weights (in kilograms) for which one repetition of a half squat can be performed and the times (in seconds) to run a 10-meter sprint for 12 international soccer players are shown in the attached data table with a sample correlation coefficient r of -0.941. A 13th data point was added to the end of the data set for an international soccer player who can perform the half squat with a maximum of 205 kilograms and can sprint 10 meters in 2.01 seconds. Describe how this affects the correlation coefficient r. Use technology. Click the icon to view the data set. The new correlation coefficient r (Round to three decimal places a going from 0.941 to - gets stronger, gets weaker, stays the same,arrow_forwardYou receive a brochure from a large university. The brochure indicates that the mean class size for full-time faculty is fewer than 31 students. You want to test this claim. You randomly select 18 classes taught by full-time faculty and determine the class size of each. The results are shown in the table below. At α = 0.05, can you support the university's claim? Complete parts (a) through (d) below. Assume the population is normally distributed. 36 28 25 27 29 35 32 39 31 28 380 22 26 29 24 27 24 30吋 24 (a) Write the claim mathematically and identify Ho and Ha. Which of the following correctly states Ho and H₂? ○ A. Ho: μ31 Нa: μ≤31 E. Ho: "=31 Ha: μ 31 OF. Ho: μ=31 Нa: μ31arrow_forwardTest the claim about the population mean μ at the level of significance α. Assume the population is normally distributed. μ Claim: <4715; α = 0.05 Sample statistics: x = 4917, s = 5501, n = 54 What are the null and alternative hypotheses? Ho: Ha (Type integers or decimals. Do not round.) Find the standardized test statistic t. t = ☐ (Round to two decimal places as needed.) Find the P-value. P = (Round to three decimal places as needed.) Decide whether to reject or fail to reject the null hypothesis. Choose the correct answer below. Ho. There enough evidence at the ☐ % level of significance to Fail to reject Reject .... the claim.arrow_forwardA politician claims that the mean salary for managers in his state is more than the national mean, $85,000. Assume the the population is normally distributed and the population standard deviation is $8700. The salaries (in dollars) for a random sample of 30 managers in the state are listed. At α = 0.01, is there enough evidence to support the claim? Use technology. 92,421 81,412 85,143 97,220 99,317 71,884 97,762 86,108 98,385 73,869 81,391 95,997 98,828 86,476 77,893 74,995 90,472 81,330 92,183 94,649 77,880 91,821 90,907 84,640 78,479 81,703 89,573 89,948 70,938 81,300 (a) Identify the null hypothesis and alternative hypothesis. O A. Ho: " =85,000 Нa: μ85,000 D. Hoi u >85,000 Нa: μ≤85,000 (b) Identify the standardized test statistic. Z= B. Hoμ≥85,000 Haμ85,000 Haμ≤85,000 (Round the final answer to two places as needed. Round all intermediate values to three places as needed.) (c) Find the P-value. Use technology. (Round to three decimal places as needed.) (d) Decide whether to reject…arrow_forwardI would like to get help to know how to make a report of the multiple regression analysis I performed about 30 employees salaries. it should include a description of the predictice model, pre-analysis, regression analysis, interpretation of the relevant findings and a conclusion with recommendations. thank youarrow_forwardTHE QUESTION: Set up a free RStudio account at posit.cloud. At the start of your R session, you should enter the following commands. set.seed(1) e<-rnorm(n = 100,mean = 0,sd = 80) x<-seq(1,100,1) y<-10+15*x + e Follow the examples in the Panopto Videos to use R to obtain the values requested below. (As always, if you round your answers, make sure you do so correctly and keep at least three decimal places.) (a) The smallest value of y = (b) The largest value of y = (c) The standard deviation of y = (d) The mean of y = (e) The median of y = (f) The correlation between x and y = (g) Using the variable e as data, the p-value for a test of Ho = 0 vs. Hд μ0 is ANSWERS I HAVE TRIED THAT ARE NOT CORRECT ↓ Answer Preview (BESIDES F, F IS CORRECT) (A) -104.123 (B) 1545.84 (C) 448.543 (D) 752.347 (E) 775.533 (F) (G) 0.987 0.497 PLEASSSEEE DO NOT GIVE ME BACK THE SAME ANSWERS THAT I HAVE SAID ARE WRONG Result incorrect incorrect incorrect incorrect incorrect correct incorrectarrow_forward3:23 Search 1 of 2 UMCISI mville.brightspace.com onomic Statistics our grade, can be done as a 2 people's group) - Due date Sunday, 12/08/202 through Brightspace portal. College students' physical, emotional, and mental health are at the forefront of many national discussions and statistical studies. Many factors can influence students' overall health, including diet, sleep, exercise, social media usage, etc. In this project, you will look at real data gathered from 30 college students and determine related descriptive and inferential statistics. Please use MS Excel (see attached file) to collect your data and complete the assignment. The students surveyed were asked the following questions: On a typical weekday, Are you an on-campus student or a commuter? How many hours of sleep do you get? How many hours do you study? How many calories do you intake? How many hours do you exercise? How many hours do you spend on social media? How many hours do you spend with your friends and family…arrow_forwardIs the area to the right of the left-tail critical value Chi-squared(1-alpha) of the chi-squared distribution always (1-alpha), and is the area to the left of this critical value always alpha? Does this apply to all chi-squared distributions?Please see image attachedarrow_forwardSet up a free RStudio account at posit.cloud. At the start of your R session, you should enter the following commands. set.seed(1) e<-rnorm(n = 100,mean = 0,sd = 80) x<-seq(1,100,1) y<-10+15*x + e Follow the examples in the Panopto Videos to use R to obtain the values requested below. (As always, if you round your answers, make sure you do so correctly and keep at least three decimal places.) (a) The smallest value of y = (b) The largest value of y = (c) The standard deviation of y = (d) The mean of y = (e) The median of y = (f) The correlation between x and y = : (g) Using the variable e as data, the p-value for a test of Hoμ = 0 vs. HA μ0 isarrow_forwardarrow_back_iosSEE MORE QUESTIONSarrow_forward_ios
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