Find the critical F-value for the following right-tailed. Test the difference between variances α= 0.01, d.f.N=2, d.f.D= 11
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Find the critical F-value for the following right-tailed. Test the difference between variances
α= 0.01, d.f.N=2, d.f.D= 11
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- Times for a surgical procedure are normally distributed. There are two methods. Method A has a mean of 31 minutes and a standard deviation of 2 minutes, while method B has a mean of 35 minutes and a standard deviation of 1.0 minutes. (a) Which procedure is preferred if the procedure must be completed within 30 minutes? O Method A O Method B O Either Method (b) Which procedure is preferred if the procedure must be completed within 38.0 minutes? O Either Method O Method A O Method B (c) Which procedure is preferred if the procedure must be completed within 37 minutes? O Method B O Either Method O Method A < Prev 19 of 19 Next to search 22 立In Company X, the personnel department gives two aptitude tests to applicants. One measures verbal ability while the other measures quantitative ability. From many years of experience, the company has found that a person's verbal score Y1 is normally distributed with mean of 50 and standard deviation (stdev) of 10. The quantitative scores Y2 are also normally distributed with mean of 100 and stdev 20. Y1 and Y2 appear to be independent. A composite score, Y, is assigned to each applicant where: Y= 3Y1 + 2Y2.Applicants whose composite scores are below 375 are automatically rejected. What is the probability that a random applicant gets automatically rejected? If six applicants submit resumes, what are the chances that fewer than half will fail the screening test?Biological oxygen demand (BOD) is a pollution index that is monitored in the treated effluent of paper mills. A certain paper mill has taken 31 samples over the past 3 months. The mean and standard deviation for the sample data are 3.42 and 0.728 ppm respectively. The mill would like to see if this sample indicates that the true average BOD in their treated effluent exceeds the targeted 3.00 ppm. Let ? = 0.05. A) The test statistic, (ttest), for this data set is: Note: Round your answer to the nearest hundredth.B) The p-value is: C) The statistical decision and corresponding English interpretation for this study are: Fail to reject Ha: conclude that the true BOD in treated effluent exceeds 3 ppmFail to reject Ho: we cannot conclude that the true BOD in treated effluent exceeds 3 ppm Reject Ha: we cannot conclude that the true BOD in treated effluent exceeds 3 ppmReject Ho: conclude that the true BOD in treated effluent exceeds 3 ppm
- If Y is Normally distributed , and p(y < 170 ) = 0.14 p ( y > 200 ) = 0.03 then the values of the mean and variance of Y , respectively areAssume that you have been provided the following information for a sample of cars The covariance between weight and miles per gallon is equal to -4.9 pound-miles. The standard deviation of the cars' mileages is 7.75. The standard deviation of the cars' weights is 0.94. Estimate the correlation coefficient to the first decimal place.Scores on a certain exam are normally distributed with a mean of 90 and a variance of 25. What is the z-value for a score of 80? -2.0 -0.4 1.0 2.0 0.4
- A researcher in a scientific foundation wished to evaluate the relation between intermediate and senior level annual salaries of research mathematician (Y, in thousand dollars) and an index of publication quality (X1), the number of years experience (X2), and an index of success in obtaining grant support (X3). A. Determine the R2 and adjusted R2. B. Determine the significant factors. C. Determine if the residual follows a normal distribution . Determine if the variance is constant over time. Find the leasts-squares regression equation. The data for a sample of 24 intermediate and senior level research mathematicians follow.Let x be a random variable that represents the pH of arterial plasma (l.e., acidity of the blood). For healthy adults, the mean of the x distribution is = 7.4.t A new drug for arthritis has been developed. However, it is thought that this drug may change blood pH. A random sample of 31 patients with arthritis took the drug for 3 months. Blood tests showed that x = 8.8 with sample standard deviations = 3.3. Use a 5% level of significance to test the claim that the drug has changed (either way) the mean pH level of the blood. A USE SALT (a) What is the level of significance? State the null and alternate hypotheses. O Hg: u + 7.4; H,: = 7.4 O Hg: H = 7.4; H,: H > 7.4 O H,: H = 7.4; H,i 7.4; H,: H = 7.4 O H: = 7.4; H,: H# 7.4 (b) What sampling distribution will you use? Explain the rationale for your choice of sampling distribution. O The Student's t, since the sample size is large a is known. O The standard normal, since the sample size is large and a is known. O The standard normal,…Our environment is very sensitive to the amount of ozone in the upper atmosphere. The level of ozone normally found is 4.6 parts/million (ppm). A researcher believes that the current ozone level is at an excess level. The mean of 14 samples is 4.9 ppm with a variance of 1.2 Does the data support the claim at the 0.01 level? Assume the population distribution is approximately normal. Step 2 of 5 : Find the value of the test statistic. Round your answer to three decimal places.
- The average score on a statistics test was 2.21 with a standard deviation of 0.88. The teacher suspects that the exam was very difficult; Based on the above, you want to adjust the scores so that the mean is 3.37 and the standard deviation is 0.25. Compute the values a and b such that the fit of type aX+b gives the desired mean and variance? Calculate: a= Answer b= Answer TIP: Use expected value and variance properties.The salaries of professional baseball players are heavily skewed right with a mean of $3.2 million and a standard deviation of $2 million. The salaries of professional football players are also heavily skewed right with a mean of $1.9 million and a standard deviation of $1.5 million. A random sample of 40 baseball players’ salaries and 35 football players’ salaries is selected. The mean salary is determined for both samples. Let represent the difference in the mean salaries for baseball and football players. Which of the following represents the shape of the sampling distribution for ? skewed right since the populations are both right skewed skewed right since the differences in salaries cannot be negative approximately Normal since both sample sizes are greater than 30 approximately Normal since the sum of the sample sizes is greater than 30
