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: 6.9, 7.5, 4.9, 6.5, 4.4, 6.2, 2.4, 7, 6.2, 5.5, 6.2, 7.3, 7.3, 8.5, 6.9, 5.6, 4.1, 3.6, 5.4, 6.7, 5.4, 5.3, 6.5, 3.2, 5.2, 8.1, 5.7, 4.5, 5.9, 2.3 Assuming the population standard deviation is σ=1.25σ=1.25, construct a 87% confidence interval for the average time it takes to complete a coronary artery bypass surgery. z α/2= Margin of Error: E= We are 87% confident that the mean amount of time it takes to complete a coronary bypass sugery is between    ? hours and     ?hours

A researcher hypothesized that cytokinins and auxins supplied by tumor-inducing insects lead to the production of tumors in plants. She performed experiments in which she hypodermically injected green pepper plants to determine if she could induce tumors. In one experiment she varied the concentration of cytokinin and the ratio of auxin concentration to cytokinin concentration. She used 3 concentrations of cytokinin and 6 ratios of auxin/cytokinin. The concentrations are indexed (1-3) with 3 indicating the highest concentration of cytokinin. The 6 ratios of auxin/cytokinin varied from 0.125 to 5.0 with values greater than 1 indicating that auxin was in greater concentration than cytokinin. The resulting data are in the date file "auxcyt.csv". The measured sizes of the tumors induced (relative to controls) are given in the 3rd column ('sumdiffd'). Analyze these data testing the appropriate hypotheses and interpret the results. (Note the unequal sample sizes.) auxcyt data…

The number of people infected with coronavirus doubles every 3.0 days. How many days does it take for the U.S. to go from one case (patient zero) to all 330,000,000 Americans being infected.

On a particular night, a baseball stadium sells 60% of its seats, and of those, 15% do not end up showing up to the game.  Assuming everyone present is sitting in a seat, what percentage of seats in the stadium are empty?

The American Heart Association is about to conduct an anti-smoking campaign and wants to know the fraction of Americans over 35 who smoke. Step 1 of 2 :   Suppose a sample of 1089  Americans over 35 is drawn. Of these people, 359 smoke. Using the data, estimate the proportion of Americans over 35 who smoke. Enter your answer as a fraction or a decimal number rounded to three decimal places.

what is the 95%CI upper and lower?

Some commercial airlines recirculate about half the air in the cabin during flights as a way to improve fuel efficiency. Other airlines make a policy of NOT recirculating the air and instead, have fresh air from the atmosphere constantly being inserted into the cabin with the “old” air being pumped out of the plane. A total of 1100 passengers flying from San Francisco to Denver were used for an experiment. After their flight, they were each given a list of symptoms associated with the common cold. They were asked to report if they experienced cold symptoms within 24 hours of the flight landing. Of the 517 passengers who flew on planes that recirculate the air, 108 reported post-flight cold symptoms. Of the 583 passengers who flew on airlines that do not use recirculation in the cabin, 110 reported symptoms. Suppose now that we want to use the recirculation of air data to explore “Goal #2”, which is to resolve a hypothesis test about . a) If we want to resolve this hypothesis…

Some commercial airplanes recirculate approximately 50% of the cabin air in order to increase fuel efficiency. The researchers studied 1100 airline passengers, among which some traveled on airplanes that recirculated air and others traveled on planes that did not recirculate air. Of the 515 passengers who flew on planes that did not recirculate air, 108 reported post-flight respiratory symptoms, while 112 of the 585 passengers on planes that did recirculate air reported such symptoms. Is there sufficient evidence to conclude that the proportion of passengers with post-flight respiratory symptoms differs for planes that do and do not recirculate air? Test the appropriate hypotheses using ? = 0.05. You may assume that it is reasonable to regard these two samples as being independently selected and as representative of the two populations of interest. (Use a statistical computer package to calculate the P-value. Use pdo not recirculate − pdo recirculate. Round your test statistic to two…

An epidemiologist studies cardiovascular disease among 25,502 male middle-aged alumni of an Ivy League university. Initial medical exams certify that the alumni have never had a heart attack in the past. During the first year of the research, 111 alums have heart attacks. Calculate the cumulative incidence per 1000 population

Lise Meitner bombarded 300 uranium atoms with a stream of neutrons for 10 seconds each.  She recorded the energy released when the uranium atom was split.  What is the sample of this study?