An environmentalist wonders whether cars get better gas mileage when using regular or premium gas. To test this, she selects 10 cars from a rental company. Each car is filled first with either regular or premium gasoline, decided by a coin toss, and the mileage for that tankful is recorded. Then the mileage is recorded again or the same cars for a tankful of the other kind of gasoline. The data is provided below: Car # 1 2 3 4 5 6 7 8 9 10 Regular 16 20 21 22 23 22 27 25 27 28 Premium 19 22 24 24 25 25 26 26 28 32   Using a hypothesis test, determine if there is evidence that cars get significantly better fuel economy with premium gasoline.

A surgeon would like to know how long it takes, on average, to complete a coronary artery bypass surgery. She samples 26 surgeries and logs the time it takes to complete each one, in hours: 5.2, 4.9, 3.9, 3.6, 5.6, 5, 4.5, 7, 4.5, 5.4, 5.1, 5.4, 5.2, 5.2, 4.1, 6.5, 6.7, 5.9, 5.4, 5.4, 5.8, 4.3, 4.7, 3.7, 5.4, 3.9 Assuming the population standard deviation is o the average time it takes to complete a coronary artery bypass surgery. 0.84, construct a 87% confidence interval for Margin of Error: E = We are 87% confident that the mean amount of time it takes to complete a coronary bypass sugery hours. hours and is between Question Help: D Post to forum

The quantity of dissolved oxygen is a measure of water pollution in lakes, rivers, and streams. Water samples were taken at four different locations in a river in an effort to determine if water pollution varied from location to location. Location I was 500 meters above an industrial plant water discharge point and near the shore. Location II was 200 meters above the discharge point and in midstream. Location III was 50 meters downstream from the discharge point and near the shore. Location IV was 200 meters downstream from the discharge point and in midstream. The following table shows the results. Lower dissolved oxygen readings mean more pollution. Because of the difficulty in getting midstream samples, ecology students collecting the data had fewer of these samples. Use a 5% level of significance. Do we reject or not reject the claim that the quantity of dissolved oxygen does not vary from one location to another? Location I Location II Location III Location IV 7.6 6.3 4.6…

The quantity of dissolved oxygen is a measure of water pollution in lakes, rivers, and streams. Water samples were taken at four different locations in a river in an effort to determine if water pollution varied from location to location. Location I was 500 meters above an industrial plant water discharge point and near the shore. Location II was 200 meters above the discharge point and in midstream. Location III was 50 meters downstream from the discharge point and near the shore. Location IV was 200 meters downstream from the discharge point and in midstream. The following table shows the results. Lower dissolved oxygen readings mean more pollution. Because of the difficulty in getting midstream samples, ecology students collecting the data had fewer of these samples. Use a 10% level of significance. Do we reject or not reject the claim that the quantity of dissolved oxygen does not vary from one location to another? Location I Location II Location III Location IV 7.1 6.6 4.3 4.7 6.7…

A company wants to study the effects a new drug has on alleviating pain.  Some patients at doctor’s office are selected to be in the study.  The patients will be randomly assigned to take the new drug or the old drug.  They will be monitored to see when the pain goes away. How many treatments are there and what are they? A. Two and which Drug received      B. One and which drug received     C. Total number of Patients     D. None.This is an obesevational study.

A surgeon would like to know how long it takes, on average, to complete a coronary artery bypass surgery. She samples 30 surgeries and logs the time it takes to complete each one, in hours: 4.7, 4.6, 4.1, 4.7, 4.7, 4.9, 4.8, 4.9, 5.7, 5.2, 4.5, 5, 4.9, 4.4, 4.7, 5.1, 5.3, 5.3, 4.2, 4.8, 4.7, 5.4, 5.4, 4.5, 5.1, 4.7, 4.6, 4.6, 4.4, 5.2 Construct a 93% confidence interval for the average time it takes to complete a coronary artery bypass surgery. S = 2 Margine of Error: E We are 93% confident that the mean amount of time it takes to complete a coronary bypass sugery is between hours and hours.

The owners of an amusement park count the number of adults and children who attend the park on a Friday and Saturday. The completed table is shown below.    Friday Saturday Total Adults 245 371 616 Children 154 277 431 Total 399 648 1,047 How does the joint frequency for the number of adults who attended the amusement park on Friday compare to the joint frequency for the number of children who attended the amusement park on Saturday?     The joint frequency for the number of adults who attended the amusement park on Friday is 399, which is less than the joint frequency for the number of children who attended the amusement park on Saturday, 431. The joint frequency for the number of adults who attended the amusement park on Friday is 154, which is less than the joint frequency for the number of children who attended the amusement park on Saturday, 277. The joint frequency for the number of adults who attended the amusement park on Friday is 371, which is…

Researchers wanted to know the effectiveness of a new allergy medicine.  A study was conducted on 500 adults who experience allergy symptoms.  Each adult was randomly assigned to receive the new allergy medicine or a placebo.  Researchers recorded whether or not their symptoms improved within 1 week. a.   Complete the two-way table summarizing the findings.   Allergy Medicine Placebo Total Symptoms Improved  85 80   Symptoms DidNot Improve         Total 215    285 500    b.  Use the study results to complete the following.  Round your answer to the nearest tenth of a percent, as needed. Notice the percent sign is already included, so you just need to type the number.  What percent of the adults in this study were given the new allergy medicine?  % What percent of those who experienced improvements received the allergy medicine?   %  What percent of those who received the allergy medicine experienced improvements?   %  What percent of those who did not received the allergy…

Several years ago, two companies merged. One of the concerns after the merger was the increasing burden of retirement expenditures. An effort was made to encourage employees to participate in the 401(k) accounts. Nationwide, 63% of eligible workers participated in these accounts. The accompanying data table contains responses of 30 employees of the company when asked if they were currently participating in a 401(k) account. Complete parts a through d. Click the icon to view the data table. a. Determine the sample proportion of company workers who participate in 401(k) accounts. The sample proportion is. (Round to three decimal places as needed.) b. Determine the sampling error if in reality the company workers have the same proportion of participants in 401(k) accounts as does the rest of the nation. The error is (Round to three decimal places as needed.) c. Determine the probability that a sample proportion at least as large as that obtained in the sample would be obtained if the…

Bicycling, the world's leading cycling magazine, reviews hundreds of bicycles throughout the year. Their "Road-Race" category contains reviews of bikes used by riders primarily interested in racing. One of the most important factors in selecting a bike for racing is the weight of the bike. The following data show the weight (pounds) and price ($) for 10 racing bikes reviewed by the magazine.† Brand Weight Price ($) FELT F5 17.8 2,100 PINARELLO Paris 16.1 6,250 ORBEA Orca GDR 14.9 8,370 EDDY MERCKX EMX-7 15.9 6,200 BH RC1 Ultegra 17.2 4,000 BH Ultralight 386 13.1 8,600 CERVELO S5 Team 16.2 6,000 GIANT TCR Advanced 2 17.1 2,580 WILIER TRIESTINA Gran Turismo 17.6 3,400 SPECIALIZED S-works Amira SL4 14.1 8,000 (a) Use the data to develop an estimated regression equation that could be used to estimate the price for a bike given the weight. (Round your numerical values to the nearest integer). ŷ = ??       (b) Compute r2. (Round your answer to three decimal…