Measurements of the length of a random sample of 200 rods made by a certain machine during one week showed a mean of 0.824m and a standard deviation of 0.042m. Find a 95% confidence interval for the mean length of all the rods.
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Q.2)a)
Measurements of the length of a random sample of 200 rods made by a certain machine
during one week showed a
95% confidence interval for the mean length of all the rods.
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- 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 54.7 inches. This average is maintained by periodically testing random samples of 25 tennis balls. If the t-value falls between - to.95 and to.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 56.9 inches and the standard deviation is 0.25 inch. Assume the bounce heights are approximately normally distributed. Is the company making acceptable tennis balls? 0 Find -to.95 and to.95. -¹0.95 = ¹0.95 (Round to three decimal places as needed.) =A researcher is interested in studying the average number of traffic violations received by male vs. female drivers. The researcher has a sample of 30 male drivers and 32 female drivers and conducts a two-sample t-test (two-tailed, alpha = .05). The researcher finds the following: 1. Male drivers have an average of 4 traffic violations every year. 2. Female drivers have an average of 2 traffic violations every year. 3. The standard error of the mean difference between male and female drivers (i.e., the se) is .50. What are the degrees of freedom for this test? Enter your answer as a whole number with no decimal places (i.e., 10, not 10.01, not 10.0, not 10.1).In a large section of a statistics class, the points for the final exam are normally distributed, with a mean of 72 and a standard deviation of 7. Grades are assigned such that the top 10% receive A's, the next 20% received B's, the middle 40% receive C's, the next 20% receive D's, and the bottom 10% receive F's. Find the lowest score on the final exam that would qualify a student for an A, a B, a C, and a D. The lowest score that would qualify a student for an A is________ (Round up to the nearest integer as needed.) The lowest score that would qualify a student for a B is_______ (Round up to the nearest integer as needed.) The lowest score that would qualify a student for a C is ______ (Round up to the nearest integer as needed.) The lowest score that would qualifty a student for a D is______ ( Round up to the nearesr integer as needed.)
- A researcher is interested in examining the difference in the average egg incubation temperature of two lizards in North Carolina, the native green anoles versus the invasive brown anoles. To investigate this, she takes two random samples from both of the lizard populations and calculates the average egg incubation temperature, standard deviation, and sample size for each of the two samples. The average incubation temperature for the 25 sampled brown anoles is 83.2 degrees Fahrenheit, with a sample standard deviation of 20.2 degrees Fahrenheit. The average incubation temperature the 28 samples green anoles is 80.1 degrees Fahrenheit, with a sample standard deviation of 17.4 degrees Fahrenheit. She has also determined that the two samples do not exhibit strong skewness and appear approximately normal. Determine the appropriate t∗ critical value for a 99% confidence interval for the difference between the true mean incubation temperatures for the two different anole species, μ1−μ2.…A company is doing a hypothesis test on the variation in quality from two suppliers. Both distributions are normal, and the populations are independent. Use a = 0.01. A sample of 22 products were selected from Supplier 1 and a standard deviation of quality was found to be 5.2696. A sample of 27 products were selected from Supplier 2 and a standard deviation of quality was found to be 3.8328. Test to see if the variance in quality for Supplier 1 is larger than Supplier 2. What are the correct hypotheses? Note this may view better in full screen mode. Select the correct symbols in the order they appear in the problem. Ho: Select an answer ? v Select an answer H1: Select an answer v Select an answer Based on the hypotheses, compute the following: Round answers to at least 4 decimal places. The test statistic is = The p-value is = The decision is to Select an answer v that the variance in The correct summary would be: Select an answer quality for Supplier 1 is larger than Supplier 2.An engineer is comparing voltages for two types of batteries (K and Q) using a sample of 71 type K batteries and a sample of 50 type Q batteries. The mean voltage is measured as 9.33 for the type K batteries with a standard deviation of 0.153, and the mean voltage is 9.68 for type Q batteries with a standard deviation of 0.366. Conduct a hypothesis test for the conjecture that the mean voltage for these two types of batteries is different. Let u be the true mean voltage for type K batteries and Hz be the true mean voltage for type Q batteries. Use a 0.05 level of significance. Step 3 of 4: Determine the decision rule for rejecting the null hypothesis Ho. Round the numerical portion of your answer to two decimal places. 囲 Tables E Keypad Answer Keyboard Shortcuts Previous Step Answers Reject Ho if Submit Answer O 2020 Hawkes Learning 7:08 AM P Search for anything A 11/25/2020
- The adult eastern hellbender (a type of giant salamander) has a length which is normally distributed with a mean of 31.8 cm and a standard deviation of 2.7 cm, while the adult Ozark hellbender has a length which is normally distributed with a mean of 34.9 and a standard deviation of 4.5. Random samples of a size 100 are selected of each species of hellbender. The box plots are created for each dataset. Which box plot will most likely have the larger interquartile range? O a. The IQR will be around the same for each. 0. O b. Either is equally likely to be larger than the other. 0 O c. The Ozark hellbenders. 0 O d. The eastern hellbenders. 0A scientist is worried about a new disease being spread by mosquitoes in an area. The scientist captures a random sample of 137 mosquitoes from the area and tests them to find out whether they carry the disease. In this sample, 22 of the mosquitoes were carrying the disease. Using this information, the scientist uses 100 simulations of additional samples with the same proportion of disease-carrying mosquitoes from the sample to determine that the standard deviation for the proportion of mosquitoes carrying the disease is approximately 0.029. What is the margin of error for the estimated proportion of mosquitoes in the area that carry the disease?A custodian wishes to compare two competing floor waxes to decide which one is best. He believes that the mean of WaxWin is greater than the mean of WaxCo. In a random sample of 40 floors of WaxWin and 43 of WaxCo. WaxWin had a mean lifetime of 26.3 and WaxCo had a mean lifetime of 28. The population standard deviation for WaxWin is assumed to be 7.1 and the population standard deviation for WaxCo is assumed to be 6.1. Perform a hypothesis test using a significance level of 0.05 to help him decide. Let WaxWin be sample 1 and WaxCo be sample 2. The correct hypotheses are: O Ho: µ1 H2(claim) Ο H: μι μp HA: H1 < µ2(claim) O Ho: µ1 = 2 HA: μι μ (claim) Since the level of significance is 0.05 the critical value is 1.645 The test statistic is: (round to 3 places) The p-value is: (round to 3 places) The decision can be made to: O reject Ho O do not reject Ho The final conclusion is that: O There is enough evidence to reject the claim that the mean of WaxWin is greater than the mean of WaxCo.…
- Suppose babies born after a gestation period of 32 to 35 weeks have a mean weight of 2500 grams and a standard deviation of 800 grams while babies born after a gestation period of 40 weeks have a mean weight of 3000 grams and a standard deviation of 385 grams. If a 32-week gestation period baby weighs 2650 grams and a 41-week gestation period baby weighs 3150 grams, find the corresponding z-scores. Which baby weighs more relative to the gestation period? Find the corresponding z-scores. Which baby weighs relatively more? Select the correct choice below and fill in the answer boxes to complete your choice. (Round to two decimal places as needed.) A. The baby born in week 41 weighs relatively more since its z-score, nothing, is smaller than the z-score of nothing for the baby born in week 32. B. The baby born in week 32 weighs relatively more since its z-score, nothing, is smaller than the z-score of nothing for the baby born in week 41. C. The…Suppose babies born after a gestation period of 32 to 35 weeks have a mean weight of 2500 grams and a standard deviation of 700 grams while babies born after a gestation period of 40 weeks have a mean weight of 2700 grams and a standard deviation of 340 grams. If a 34-week gestation period baby weighs 2275 grams and a 40-week gestation period baby weighs 2475 grams, find the corresponding z-scores. Which baby weighs less relative to the gestation period?An electrical engineer wishes to compare the mean lifetimes of two types of transistors in an application involving high-temperature performance. A sample of 60 transistors of type A were tested and were found to have a mean lifetime of 1827 hours and a standard deviation of 174 hours. A sample of 180 transistors of type B were tested and were found to have a mean lifetime of 1658 hours and a standard deviation of 231 hours. Let ux represent the population mean for transistors of type A and µy represent the population mean for transistors of type B. Find a 95% confidence interval for the difference uy – µy . Round the answers to three decimal places. The 95% confidence interval is
