Problem 2: Two different analytical tests can be used to determine the impurity level in steelalloys. Nine specimens are tested using both procedures, and the results are shown in thefollowing table:Specimen1234567891.186 1.151 1.322 1.3391.061 0.992| 1.063 | 1.062 1.065| 1.178| 1.037 1.086 | 1.052Test11.2 1.402 1.365 1.537 1.559Test2Paired Samples TestPaired Differences95% Confidence Interval of theDifferenceMeanStd. Deviation Std. Error MeanLowerUpperdfSig. (2-tailed)Pair 1Test1 - Test2.135099.377736 6.0828.273889.045033.170042.0001- Is there sufficient evidence to conclude that both tests give the same mean impuritylevel, use a significance level of 0.05?2- Find a 95% confidence interval for the mean difference between the Test1 and Test2?

The given information indicates the output of Paired Samples T-test.

Answered: Problem 2: Two different analytical…

MATLAB: An Introduction with Applications

6th Edition

ISBN:9781119256830

Author:Amos Gilat

Publisher:Amos Gilat

Chapter1: Starting With Matlab

Section: Chapter Questions

Problem 1P

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Problem 2:Examine the relationship between amount of time spent studying for an exam (X) in hours andthe score that person makes on an exam (Y)X Y2 653 703 754 705 856 857 90 using spss Give the following:1. Null hypothesis2. Alternative hypothesis3. Statistical test4. Computation5. Decision6. Conclusion
Two different analytical methods were used to determine residual chlorine in sewage effluents. Both methods were used on the same samples, but each sample came from various locations with differing amounts of contact time with the effluent. Two methods were used to determine the concentration of Cl in mg/L, and the results are shown in the following table: Sample Method A Method B 1 0.39 0.36 2 0.84 1.35 3 1.76 2.56 4 3.35 3.92 5 4.69 5.35 6 7.70 8.33 7 10.52 10.70 8 10.92 10.91 a) What type of t-test should be used to compare the two methods and why? b) Do the two methods give different results? State and test the appropriate hypotheses. c) Does the conclusion depend on whether the 90%, 95%, or 99% confidence levels are used?
The mean ±1 sd of ln [calcium intake (mg)] among 25females, 12 to 14 years of age, below the poverty level is6.56 ± 0.64. Similarly, the mean ± 1 sd of ln [calcium intake(mg)] among 40 females, 12 to 14 years of age, above thepoverty level is 6.80 ± 0.76. A.What is the appropriate procedure to test for a significant difference in means between the two groups?B. Implement the procedure in Problem 8.3 using theD.critical-value method.C. What is the p-value corresponding to your answer toProblem 8.4? Compute a 95% CI for the difference in meansbetween the two groups.
Two different analytical methods were used to determine residual chlorine in sewage effluents. Both methods were used on the same samples, but each sample came from various locations with differing amounts of contact time with the effluent. Two methods were used to determine the concentration of Cl in mg/L, and the results are shown in the following table: Answer the following questions as per the table: - 1.What type of t test should be used to compare the two methods and why? 2.Do the two methods give different results? State and test the appropriate hypotheses. 3.Does the conclusion depend on whether the 90%, 95%, or 99% confidence levels are used?
QUESTION 25 A clinical trial is being conducted in order to determine the efficacy of a new drug used to treat Rheumatoid arthritis. The efficacy of the medication will not only be determined by the physical improvement of symptoms but also by using a blood test to examine the concentration C-reactive protein (an inflammatory marker) in an individual’s blood. If the researcher wants a margin of error for the level of C-reactive protein to be less than or equal to 3.0 mg/dL, and if the standard deviation for C-reactive protein concentrations among arthritis patients was previously documented at 8 mg/dL, how many patients should be recruited for each group in the study assuming a 95% confidence interval will be used to quantify the mean differences between the control group and the treatment group? nfor the treatment group = 112; n for the control group = 111 nfor the treatment group = 56; n for the control group = 57 nfor the treatment group = 55; n…
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The Prevalence per 10,000 population of having health insurance for 1 (Table 5 box s. above) is: The Prevalence per 10,000 population of having health insurance for 2 (Table 5 box w. above) is:
As part of the study described in Problem 6, investigators wanted to assess the accuracy of self-reported smoking status. Participants are asked whether they currently smoke or not. In addition, laboratory tests are performed on hair samples to determine presence or absence of nicotine. The laboratory assessment is considered the gold standard, or truth about nicotine consumption. The data are as follows: Nicotine Absent Nicotine Present Self-reported nonsmoker 90 17 Self-reported smoker 10 50 What is the specificity of self-reported smoking status? A)1 B)0.1 C)0.84
Problem 6: Please answer parts a and b! (a) A genetic model suggests that 80% of plants grown from a cross between two given strains of seeds will be of the dwarf variety. After breeding 201 of these plants, 153 were observed to be of the dwarf variety. Do these data strongly contradict the genetic model? Find the p-value. (b) At the 1% significance level, what is the conclusion of the above hypothesis test?
Problem 3. Suppose a test for detecting a certain rare disease has been perfected that is capable of discovering the disease in 97% of all afflicted individuals. Suppose further that when it is tried on healthy individuals, 5% of them are incorrectly diagnosed as having the disease. Finally, suppose that when it is tried on individuals who have certain other milder diseases, 10% of them are incorrectly diagnosed. It is known that the percentages of individuals of the three types being considered here in the populations at large are 1%, 96%, and 3%, respectively. Calculate the probability that an individual, selected at random from the population at large and tested for the rare disease, actually has the disease if the test indicates he is so afflicted.
The following data were collected in the study described in Problem 1 relating hypertensive status measured at baseline to incident stroke over 5 years. Free of Stroke at 5 Years Stroke Baseline: Not Hypertensive 932 58 Baseline: Hypertensive 254 106 Compute the incidence of stroke in this study, overall. 0.294 0.121 0.059 0.879
Question 1 For the following scenarios provide the following: • the null and alternative hypotheses • explain whether the hypothesis test is left-tailed, right-tailed, or two-tailed, • explain how you should interpret a decision that rejects the null hypothesis, and • explain how you should interpret a decision that fails to reject the null hypothesis. a. A meal supplement provider claims that the average difference in calories between two brands is 55.

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