A manufacturer of flashlight batteries claims that the average life of her batteries is larger than 400 hours. Peter, as a quality assurance officer in the manufacturing company, took a random sample of 13 batteries from a day's production and used them continuously until they failed to work. The lifetime (hours) until failure was: 342 426 317 545 264 451 1049 631 512 266 492 562 298 (a) At the 0.05 level of significance, is there evidence that the manufacturer's claim is correct? (b) What is the n-value?
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- A new screening test for thyroid cancer was administered to 1,000 adult volunteers at a large medical center complex in Europe. The results showed that 152 out of 160 diagnosed cases of thyroid cancer were correctly identified by the screening test. Also, of the 840 individuals without thyroid cancer, the screening test correctly identified 714. Base on this information, calculate the test's: 1. Sensitivity 2. Specificity 3. Positive predictive value 4. Negative Predictive Value 5. Accuracy 6. Prevalence rate. Please help with 4,5,6. I have attached 1,2,3.The average worker at a local brake manufacturer produces 10 brakes per day (other statistical information was not known). An industrial psychologist was hired to increase worker productivity and a new assembly method was designed and tested in a sample of workers. Identify the appropriate test. Select one: a. independent samples t test b. z test c. single sample t test d. paired samples t testA manufacturer of children's vitamins claims that its vitamins are mixed so that each batch has exactly the following percentages of each color: 10 % green, 30 % yellow, 30 % red, and 30 % orange. To test the claim that these percentages are incorrect, 100 bottles of vitamins were sampled and the colors of the vitamins were tallied. The results are listed in the following table. At a = 0.025, determine whether there is sufficient evidence to conclude that the percentages stated by the vitamin manufacturer are incorrect. Children's Vitamins Green Yellow Red Orange Number 590 1765 1717 1615 Copy Data Step 2 of 4: Calculate the expected value for the number of vitamins that are orange. Round your answer to three decimal places, if necessary.
- An automobile dealer conducted a test to determine if the time in minutes needed to complete a minor engine tune-up depends on whether a computerized engine analyzer or an electronic analyzer is used. Because tune-up time varies among compact, intermediate, and full-sized cars, the three types of cars were used as blocks in the experiment. The data obtained follow. Analyzer Computerized Electronic Compact 50 41 Car Intermediate 56 44 Full-sized 62 47 Use a = 0.05 to test for any significant differences. State the null and alternative hypotheses. O Ho: Hcompact * HIntermediate * HFull-sized Ha: "Compact = HIntermediate = 4Full-sized O Ho: HComputerized * HElectronic Ha: HComputerized = HElectronic O Ho: HComputerized = HElectronic Ha: "Computerized * HElectronic O Ho: HComputerized = HElectronic = "Compact = HIntermediate = "Full-sized H.: Not all the population means are equal. O Ho: HCompact = HIntermediate = HFull-sized Hai H compact * HIntermediate * HFull-sized Find the value of…Citrus Rental is a popular car rental agency that has a history of having too few cars available, so that its available cars are overdriven. The mean monthly mileage over the years for Citrus cars has been about 1550 miles per month. Recently, though, Citrus purchased thousands of new cars, and the company claims that the average mileage of its cars is now less than in the past. To test this, a random sample of 15 recent mileages of Citrus cars was taken. The mean of these 15 mileages was 1517 miles per month, and the standard deviation was 201 miles per month. Assume that the population of recent monthly mileages of Citrus cars is normally distributed. At the 0.05 level of significance, can it be concluded that the mean recent monthly mileage, μ, of Citrus cars is less than 1550 miles per month? Perform a one-tailed test. Then complete the parts below.A company manufactures tennis balls. When its tennis balls are dropped onto a concrete surface from a height of 100 inches, the company wants the mean height the balls bounce upward to be 54.8 inches. This average is maintained by periodically testing random samples of 25 tennis balls. If the t-value falls between −t0.95 and t0.95, then the company will be satisfied that it is manufacturing acceptable tennis balls. A sample of 25 balls is randomly selected and tested. The mean bounce height of the sample is 56.3 inches and the standard deviation is 0.25 inch. Assume the bounce heights are approximately normally distributed. Is the company making acceptable tennis balls?
- A new screening test for Lyme disease is developed for use in the general population. The sensitivity and specificity of the new test are 60% and 70%, respectively. Five hundred people are screened at a clinic during the first year the new test is implemented. Assume the true prevalence of Lyme disease among clinic attendees is 10%. Calculate the predictive value of a positive test.Water samples are taken from water used for cooling as it is being discharged from a power plant into a river. It has been determined that as long as the mean temperature of the discharged water is at most 150°F, there will be no negative effects on the river's ecosystem. To investigate whether the plant is in compliance with regulations that prohibit a mean discharge water temperature above 150°, 50 water samples will be taken at randomly selected times and the temperature of each sample recorded. The resulting data will be used to test the hypotheses Ho: μ = 150° versus H₂: μ > 150°. In the context of this situation, describe type I error. a A type I error occurs when our estimate for the mean discharge temperature is higher than the actual temperature. A type I error occurs when we say that the plant is not in compliance when in fact it is. A type I error occurs when our estimate for the mean discharge temperature is lower than the actual temperature. A type I error occurs when we…A manufacturer of children's vitamins claims that its vitamins are mixed so that each batch has exactly the following percentages of each color: 20 % green, 30 % yellow, 30% red, and 20% orange. To test the claim that these percentages are incorrect, 100 bottles of vitamins were sampled and the colors of the vitamins were tallied. The results are listed in the following table. At a = 0.025, determine whether there is sufficient evidence to conclude that the percentages stated by the vitamin manufacturer are incorrect. Number Children's Vitamins Green 906 I Yellow 1321 Porange Red 1306 Copy Data Step 1 of 4: State the null and alternative hypotheses in terms of the expected proportion for each color of vitamin. Ho:P green = - Pyellow = _Pred = Ha: There is a difference from the stated proportions. Orange 778
- Suppose an experiment finds that people taking a new herbal remedy get fewer colds than people taking a placebo. The results are statistically significant at the 0.01 level. Has the experiment proven that the herbal remedy works?Recent results suggest that children with ADHD tend to watch more TV than children who are not diagnosed with the disorder. To examine this relationship, a researcher obtains a random sample of n = 36 children, 8 to 12 years old, who have been diagnosed with ADHD. Each child is asked to keep a journal recording how much time each day is spent watching TV. The average daily time for the sample is M = 4.9 hours. It is known that the average time for the general population of 8 to 12-year-old children is = 4.1 hours with = 1.8. (Hint: Be sure to use the correct test statistic). Are the data sufficient to conclude that children with ADHD watch significantly more TV than children without the disorder? Use a two-tailed test with = .05. (Be sure to give your conclusion, too) If the researcher had used a sample of n = 9 children and obtained the same sample mean, would the results be sufficient to reject H0? (Be sure to give your conclusion, too) Compute Cohen's d for this study. What is…Dr. Maddan's eye drops are supposed to cause significant reduction is eye redness. The following table shows the results of a recent study where a random sample of individuals took part in a placebo controlled study. No Reduction in Redness Reduction in Redness Total Eye Drops 120 220 340 No Eye Drops Total 120 140 260 240 360 600 With 5% level of significance, determine if eye redness reduction is dependent upon taking the eye drops. Provide, a. the Chi-square statistic. b. the critical value or the p-value. c. Your decision on whether or not to reject Ho.