Statistics question and answers for August 13, 2023
- Q Find the 90% confidence interval for the standard deviation ofthe lengths of pipes if a sample of 22 pipes has a standarddeviation of 10.6 inches.a. (8.3, 13.8)b. (8.5, 13.3)c. (8.5,...
- Q The method of tree ring dating gave the following years A.D. foran archaeological excavation site. Assume that the population ofx values has an approximately normal distribution.119413061264118012681316127513171275(a) Find a 90% confidence...
- Q A population is normally distributed with μ=300 and σ=20.A. Find the probability that a value randomly selected from thispopulation will have a value greater than 345B. Find the probability that...
- Q a.Describe the Pooled variance assumption. How does it change thestandard error? What impact does it have on a test statistic? Whatimpact does it have on a p-value?How do you justify...
- Q Let x be a random variable that represents white bloodcell count per cubic milliliter of whole blood. Assume thatx has a distribution that is approximately normal, withmean μ = 6750...
- Q Coal is carried from a mine in West Virginia to a power plant inNew York in hopper cars on a long train.The automatic hopper car loader is set to put...
- Q For a regression of test score (T) on the endogenous variablestudent-teacher ratio (R), Hoxby (2000) suggests using as aninstrument the deviation of potential enrollment from its long-termtrend (P), where \"potential...
- Q The assets​ (in billions of​ dollars) of the four wealthiestpeople in a particular country are 37, 35, 31, 18. Assume thatsamples of size n=2 are randomly selected with replacement fromthis...
- Q The marital status distribution of the U.S. male population, age15 and older, is as shown below.Marital StatusPercentnevermarried31.3married56.1widowed2.5divorced/separated10.1Suppose that a random sample of 400 U.S. young adult males, 18to 24 years...
- Q If a researcher found that there was a correlation of r = -0.67between the number of siblings a person has and introversion, andthe researcher sampled n = 30 people, what...
- Q A software developer wants to know how many new computer gamespeople buy each year. A sample of 164 people was taken to studytheir purchasing habits. Construct the 80% confidence interval...
- Q Benford's Law states that the first nonzero digits of numbersdrawn at random from a large complex data file have the followingprobability distribution.†First Nonzero Digit123456789Probability0.3010.1760.1250.0970.0790.0670.0580.0510.046Suppose that n = 275 numerical entries...
- Q Accrotime is a manufacturer of quartz crystal watches. Accrotimeresearchers have shown that the watches have an average life of 26months before certain electronic components deteriorate, causingthe watch to become unreliable....
- Q You are the foreman of the Bar-S cattle ranch in Colorado. Aneighboring ranch has calves for sale, and you are going to buysome calves to add to the Bar-S herd....
- Q Give one strength and one limitation of each these study designsfor studying a disease and an exposure: randomized clinical trial,population-based (cross-sectional) study and case-control study(disease-based). Which study design is better...
- Q The concerns about the impact of technology on our lives aregrowing. There have been recent research reports about the negativeimpact of digital technology usage on​ stress, work​ productivity,happiness, and overall​...
- Q A sample of 114 patients were given a drug to lower cholesterol.A 95% confidence interval for the mean reduction in cholesterol (inmmol/L) was (0.88, 1.02). What was the sample standard...
- Q Please submit your Excel file and highlight your answers incolor. Brief Case Has Gold Lost its Luster? In 2011, when theGallup organization polled investors, 34% rated gold the bestlong-term investment....
- Q a. The following are the GPA's of a class of Stats students:3.4, 3.1, 2.0, 2.3, 3.3, 2.6, 1.8, 0.2, 3.1, 4.0, 0.7, 2.3,Construct the 99% CI.b.Would a 90% CI be...
- Q Drug A is the usual treatment for depression in graduatestudents. Pfizer has a new drug, Drug B, that it thinks may be moreeffective. You have been hired to design the...
- Q An engineer has designed a valve that will regulate waterpressure on an automobile engine. The valve was tested on 140engines and the mean pressure was 7.7 lbs/square inch. Assume thevariance...
- Q Researchers measured the amount of plasma carotenoids (inmicrograms per milliliter) of male and female zebra finches. Hereare some summary statistics from the study (note: standarderror=standard deviation/sqrt(n)):SexnMeanStandard ErrorMales5031.771.85Females5229.742.02Do male and female...
- Q Researchers aim to study the weights of 10-year-old girls livingin the United States (possibly to compare to other countries andthus compare growth rates). Based on previous studies, we canassume that...
- Q A newsgroup is interested in constructing a 90% confidenceinterval for the proportion of all Americans who are in favor of anew Green initiative. Of the 588 randomly selected Americanssurveyed, 354...
- Q A journalist once wrote aboutTiger Woods’ ability to detect subtle differences in golfequipment. Tiger Woods was sent four golf clubs to test. The fourclubs looked identical, but one was heavier...
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