In Exercises 5–20, assume that the two samples are independent simple random samples selected from
19. Is Old Faithful Not Quite So Faithful? Listed below are time intervals (min) between eruptions of the Old Faithful geyser. The “recent” times are within the past few years, and the “past” times are from 1995. Does it appear that the mean time interval has changed? Is the conclusion affected by whether the significance level is 0.05 or 0.01?
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Elementary Statistics (13th Edition)
- In the period of 2010 – 2020 in the United States 1/3 of patients 55 years old or older had a seasonal flu vaccine. The risk of death for a flu-vaccinated person 55 years or older in the following 10 months is 0.6 deaths per 1,000 flu-vaccinated persons 55 years old or older. The risk of death for a non-vaccinated 55 year old or older person in the same 10 month period is 5 deaths per 1,000. Given these numbers, what is the probability that a person 55 years or older in the United States will survive 10 months into that year's flu season?arrow_forwardPart Darrow_forward(All one question just could not fit into one picture)arrow_forward
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- The proportion of adults living in a small town who are college graduates is estimated to be p = 0.5. To test this hypothesis, a random sample of 10 adults is selected. If the number of college graduates in the sample is anywhere from 3 to 7, we shall not reject the null hypothesis that p = 0.5; otherwise, we shall conclude that p + 0.5. Complete parts (a) through (c) below. Click here to view page 1 of the table of binomial probability sums. Click here to view page 2 of the table of binomial probability sums. Click here to view page 3 of the table of binomial probability sums. %3D (a) Evaluate a assuming that p = 0.5. Use the binomial distribution. (Round to four decimal places as needed.)arrow_forwardSuppose that arrival times at a certain emergency care center are following a Poisson process with a mean rate of λ= 0.2 arrivals per minute. Let T be the time until the third arrival. Find the mean and the variance of T, and find P(T ≤30) to four decimal places. Part 1 out of 3The mean of T is ________minutes.arrow_forwardSuppose data shows that only 50% of breast cancer patients can survive more than 5 years. You suspect the claimed survival rate is too low, so you'd like to conduct a study to examine this situation. What is the null and alternative hypothesis in this situation? Let p represent the true percentage of breast cancer patients who survive more than 5 years. Ho p=0.5 v.s. Ha p > 0.5 Ho p=0.5 v.s. Ha : p 0.5arrow_forward
- II. Conduct a hypothesis test A research center claims that less than 50% of senior high school students in public schools in the Philippines have accessed the Internet using cellular phones. In a random sample of 100 SHS students, 39% say they have accessed the Internet using cellular phones. At = 0.01, is there enough evidence to support the researcher's claim?arrow_forward, 16. A statistically minded fraternity junior keeps records on how many girls he has to ask before one agrees to be his date for a Saturday football game. His school plays five home games and his five acceptances come on the 3rd, 6th, 4th, 2nd, and 9th girl he asks. Assume that the probability, e, that any girl he asks will accept his invitation is constant from girl to girl. Mind ML estimate of e.arrow_forwardBighorn sheep are beautiful wild animals found throughout the western United States. Let x be the age of a bighorn sheep (in years), and let y be the mortality rate (percent that die) for this age group. For example, x = 1, y = 14 means that 14% of the bighorn sheep between 1 and 2 years old died. A random sample of Arizona bighorn sheep gave the following information: x 1 2 3 4 5 y 14.2 17.7 14.4 19.6 20.0 Σx = 15; Σy = 85.9; Σx2 = 55; Σy2 = 1,506.45; Σxy = 271.2 (a) Find x, y, b, and the equation of the least-squares line. (Round your answers for x and y to two decimal places. Round your least-squares estimates to three decimal places.) x = y = b = ŷ = + x (b) Draw a scatter diagram for the data. Plot the least-squares line on your scatter diagram. (c) Find the sample correlation coefficient r and the coefficient of determination r2. (Round your answers to three decimal places.) r = r2 = What percentage of variation in y is explained…arrow_forward
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