4. Triclоsаn is а cоmpоund often аdded to products such as soaps, lotions, and toothpaste. It is antimicrobial, so we expect it to lower one's chance of having a staph infection. However, the opposite was found in a recent study.1 Microbiologists swabbed the noses of 90 people, and recorded which had detectable levels of triclosan and which had evidence of carrying the staph bacteria, which greatly increases one's chance of having a serious staph infection. The results are shown in the table below. Use the results of this study to estimate the difference in the proportion of people with staph bacteria, between those with triclosan in their system and those without (proportion for those who have triclosan in their system – proportion for those who do not have triclosan in their system). (As a result of this study and others, the US Food and Drug Administration is investigating whether adding triclosan to personal care products is safe and effective.) 1Mole B, "Triclosan aids nasal invasions by staph," Science News, April 15, 2014. Click here to access StatKey. Staph No Staph Total Triclosan 24 13 37 No Triclosan 15 38 53 Total 39 51 90 Let group 1 be people with staph infections of all people with triclosan in their system and let group 2 be people with staph infections of all people who do not have triclosan in their systems.(a) Give notation for the parameter we are estimating. ____________(b) Give notation for the best estimate. __________(c) Give the value of the best estimate. Round your answer to three decimal places. _____________(d) The 99%confidence interval. Round to three decimal places .__________ to ________________.(e) Interpret the interval: _____________________________________________________________(f)Can we conclude that people with triclosan in their systems are more likely to have staph infections? ___________ (Yes or No)Can we conclude that triclosan causes the increase in staph infections? __________(Yes or No)
A cоrpоrаtiоn is considering the purchаse of а factory machine that would cost $ 349,472, would have a useful life of 7 years, and would have no salvage value. The machine would allow the company to earn additional net cash inflows of $81,500 per year.The internal rate of return on the investment in the machine is closest to:Present Value of $1; 1 ( 1 + r ) nPeriod4%5%6%7%8%9%10%11%12%13%14%15%10.9620.9520.9430.9350.9260.9170.9090.9010.8930.8850.8770.8720.9250.9070.890.8730.8570.8420.8260.8120.7970.7830.7690.75630.8890.8640.840.8160.7940.7720.7510.7310.7120.6930.6750.65840.8550.8230.7920.7630.7350.7080.6830.6590.6360.6130.5920.57250.8220.7840.7470.7130.6810.650.6210.5930.5670.5430.5190.49760.790.7460.7050.6660.630.5960.5640.5350.5070.480.4560.43270.760.7110.6650.6230.5830.5470.5130.4820.4520.4250.40.37680.7310.6770.6270.5820.540.5020.4670.4340.4040.3760.3510.327Present Value of an Annuity of $1 in Arrears; 1 r [ 1 - 1 ( 1 + r ) n ]Period4%5%6%7%8%9%10%11%12%13%14%15%10.9620.9520.9430.9350.9260.9170.9090.9010.8930.8850.8770.8721.8861.8591.8331.8081.7831.7591.7361.7131.691.6681.6471.62632.7752.7232.6732.6242.5772.5312.4872.4442.4022.3612.3222.28343.633.5463.4653.3873.3123.243.173.1023.0372.9742.9142.85554.4524.3294.2124.13.9933.893.7913.6963.6053.5173.4333.35265.2425.0764.9174.7674.6234.4864.3554.2314.1113.9983.8893.78476.0025.7865.5825.3895.2065.0334.8684.7124.5644.4234.2884.1686.7336.4636.215.9715.7475.5355.3355.1464.9684.7994.6394.487