Statistics Case Study 1 Essay Example For Students

Statistics Case Study 1 Essay Statistics Case Study-1 AgeWeeks Employed 5521 3018 2311 5236 4119 2512 427 4525 256 4021 2513 2511 5934 4927 3318 3520 a. AgeWeeks Employed Mean37.75Mean18.6875 Standard Error2.974195Standard Error2. We will write a custom essay on Statistics Case Study 1 specifically for you for only $16.38 $13.9/page Order now 188452 Median37.5Median18.5 Mode25Mode21 Standard Deviation11.89678Standard Deviation8.753809 Sample Variance141.5333Sample Variance76. 62917 Kurtosis-1.17143Kurtosis-0.21626 Skewness0.337402Skewness0.522601 Range36Range30 Minimum23Minimum6 Maximum59Maximum36 Sum604Sum299 Count16Count16 Confidence Level(99.0%)8. 764138Confidence Level(99.0%)6.44877 b. 99% confidence interval estimate for mean age of newly hired employees; 37.75 V 8.76 = 28. 99 to 37.75 + 8.76 = 46.51 c. Hypothesis: Decision Rule: Reject Ho if t t-critical Do not reject Ho if t t-critical t-critical = t0.01,15 =2. 602 0.771 2.602 Therefore, at a 99% Confidence Level the Null Hypothesis can not be rejected and we can not state that Riversides mean duration of employment weeks is any greater than the mean duration of employment weeks within the rest of California. d. Is there a relationship between the age of a newly employed individual and the number of weeks of employment? By using a scatter plot and plotting the number of weeks employed in respect to the ages of the workers, you can see that the points are distributed along a straight line. The number of weeks employed increase positively as the age of the worker increases. Therefore it is safe to say that there is a positive correlation between the ages of newly employed workers and the number of weeks they are employed. Textbook Exercise 7.6, The Trash Bag Case Text Problem 7.6: n =40 mean =50.575 std dev. =1. 6438 a. 95% =0.509408783m =50.06559122 m =51.08440878 99% =0.669478969m =49. 90552103 m =51.24447897 b.Yes, we can be 95% confident that the trash bags are at least 50 pounds in strength because the lower confidence level is slightly more than 50 at 50.06 pounds. c.No, we can not be 99% confident that the trash bags are at least 50 pounds in strength because the lower confidence level is slightly less than 40 at 49. 9 pounds. d.Even though I can not say for sure with 99% confidence that the trash bags have a 50 pound strength, the lower confidence level is very close at 49.9 pounds. Since no other trash bag on the market has a breaking strength of 50 pounds, I think that I can say in good confidence that this bag is the strongest bag on the market. Textbook Problem 8. 76: a. ,do not reject, the manufacturers claim is true , reject the null, the manufacturers claim is false b. Sample size is 30 so therefore we can use z-statistics. (316/400 V 0.95)/0.95*(1-0. 95)/4001/2 = -14.683 So, if given a significant level (N), if z-stat -ZN, then reject null hypothesis and accept alternative hypothesis. a-ZNAction on null hypothesis 0.10-1.282Reject 0.05-1. 645Reject 0.01-2.326Reject 0.001-3.090Reject From the above information it can be concluded that the manufacturers claim is false. c. Not really because the manufacturer claims that their television sets last at least 5 years without needing repairs but the sample collected was from consumers that owned their sets for 5 years and not beyond. In order for the results of the survey to have practical importance we would need to sample consumers that have owned their sets for 5 or more years. Palmer vs. Woods: Woods,1999 Palmer,1960 mean =69.56mean =69.95 N=84N=112 std dev. =2.5std dev. =2.5 .

Chemistry Notes Essays

Chemistry Notes Essays Chemistry Notes Paper Chemistry Notes Paper Chemistry 200 Exam 1 Review Problems 1. Calculate the number of atoms in 10. 0 grams of Fe. 2. Give the mass number, #protons, #neutrons and #electrons for the isotope strontium-88. 3. Calculate the number of moles of carbon in 50. 0 g of benzene C6H6 4. A substance is found to be 38. 7 % C, 9. 7 % H and 51. 6 % O by mass. Its molar mass is 62. 1 g/mole. What is its molecular formula? 5. Name the following: a) Ca(OH)2b) KCN c) HClO4(aq)d) FeSO4e) Na2O f) SF6g) MgSO4 ( 2H2Oh) Na2O2 6. What are the formulas of the following compounds? ) sodium sulfite b) potassium permanganatec) calcium sulfide d) aluminum hydroxidee) mercury (II) phosphate f) tetraphosphorus trisulfideg) nitrous acid 7. Which of the following is not an example of a chemical change? a) converting gasoline to carbon dioxide and water b) digesting starch to give glucose c) grinding sucrose crystals into powdered sugar d) smoking tobacco e) generating carbon dioxide from baking soda and vinegar 8. The density of ethyl alcohol is 0. 789 g/mL. What is the volume of 35. 5 grams of ethyl alcohol ? 9. How many significant figures are in the mass measurement 0. 50 gram? 10. If an automobile engine has a volume of 155 in3, what is the volume in cm3 ? (2. 54 cm = 1 in exactly) 11. Convert 25 ? L into milliliters 12. If 5. 58 g of powdered iron react with powdered sulfur to produce 8. 79 g of iron sulfide, what is the mass of reacting sulfur? 13. Sodium chloride, table salt, melts at 801 °C. What is the melting point on the Fahrenheit scale ? 14. Express this number in scientific notation: 0. 00104 centimeter 15. What is the mass in kilograms of a beaker that weighs 101 grams? 16. Convert 12 g(cm2/s2 to Joules (kg(m2/s2) 17. A 1. 13 g sample of a hydrate, ZnSO4 ( X H2O is dissolved in pure water and the sulfate ion is precipitated by adding an excess of barium chloride solution. The mass of pure dry barium sulfate obtained is 0. 8223 g. What is the formula of the zinc hydrate? 18. 0 . 01981 g of an acid containing only C, H, and O undergoes combustion to yield 0. 04198 g carbon dioxide and 0. 00645 g water. What is the empirical formula of the acid? 19. The maximum allowable concentration of carbon monoxide in urban air is 10 mg/m3 over an eight-hour period. At this level, what mass of CO in grams is present in a room measuring 8. x 12. 0 x 20. 0 ft ? 20. An English unit used in pharmaceutical work is the grain (gr). There are 15 grains in 1 gram. An aspirin tablet contains 5. 0 gr of aspirin. A 145 lb person takes two aspirin tablets. Calculate the dosage of aspirin, which is the number of milligrams of aspirin per kilogram of body weight. (1 lb = 453. 5 g) 21. The dosage of an arthritis medicine for dogs is given as 1. 5 – 1. 7 mg / kg body weight. If my dog weighs 70. lbs, and the drug comes as 100 mg tablets, how many tablets should my dog get? (1 lb = 453. 5 g) True or False 22. A compound is a pure substance that cannot be broken down any further by ordinary chemical reaction. 23. Li2O is dilithium oxide. 24. The nucleus of one atom of 18O contains 18 neutrons and 8 protons. 25. The name of the family of potassium is â€Å"alkali metal. 26. Sodium chloride is a mixture. 27. All atoms of an element have the same mass. More Calculations: 28. Given the reaction:2C2H6 + 7O2 ( 4CO2 + 6H2O How many moles of O2 will react completely with 12. 00 moles of C2H6 ? 29. Given the equation:4FeS2 + 11O2 ( 2Fe2O3 + 8SO2 If you react 85 grams of FeS2 with excess O2 , how many grams of Fe2O3 should you get? 0. Given the reaction: 2C2H6 + 7O2 ( 4CO2 + 6H2O If 28. 0 grams of C2H6 are reacted with excess oxygen, and 70. 0 grams of CO2 are produced , what is the percent yield of the reaction? 31. Given the reaction: 2 H2 + O2 ( 2 H 2O If 15. 0 g of H2 are mixed with 15. 0 g of O2 what mass of water is produced? 32. What is the molarity of a HCl(aq) solution made by dissolving 0 . 20 moles of HCl(g) in enough water to make 40. 0 mL of solution? 33. What mass of NaOH(s) is required to prepare 250 mL of 50. 0 mM NaOH(aq)? (note: what does mM (millimolar) mean? 34. How many mL of 12 M HCl(aq) do you need to prepare 150. 0 mL of 1. 5 M HCl(aq)? 35. If 75. 0 g of Na2SO4 are dissolved in water to make 1. 50 L of solution, what are the concentrations (molarity) of all the ions in the final solution? 36. If 0. 203 g of KHP (potassium hydrogen phthalate) is titrated with 10. 7 mL of NaOH (aq) , what is the molarity of the NaOH solution? (molar mass KHP = 204. 22) KHP + NaOH ( H2O + salt 37. Given the following equation: 3 NiSO4 (aq) + 2 Na3PO4 (aq) ( Ni3(PO4)2 (s) + 3 Na2SO4 (aq) How many mL of 0. 75 M NiSO4 (aq) are needed to react completely with 35. 6 mL of 0. 265 M Na3PO4 (aq)? 38. Element X has three naturally occurring isotopes. The masses (amu) and % abundances of the isotopes are given in the table below. The average atomic mass of the element is __________ amu. [pic] 39. Provide the products of the following reaction: C6H10 + O2 > What type of reaction is this? 40. Given the following equation: 3 NiSO4 (aq) + 2 Na3PO4 (aq) ( Ni3(PO4)2 (s) + 3 Na2SO4 (aq) If 20. 0 mL of 0. 100 M NiSO4 is reacted with 35. 0 mL of 0. 100 M Na3PO4 how many grams of Ni3(PO4)2 are produced?

Network Security Essay Example | Topics and Well Written Essays - 2000 words - 1

Network Security - Essay Example Many cyber attacks are tackled through the Kaspersky antivirus. The security is dealt from many aspects by Kaspersky antivirus. Some of these aspects are as work regarding stealing of information, process of blocking for infrastructure, the stealing of money, destroying the repute of particular targeted organization. Many other techniques of intrusion are detected and explored for giving the enhanced security protection to the underlying system. (Kaspersky Lab ZAO, 2011). Kaspersky network security is the cloud based antivirus. It gathers data from the millions of its users’ systems around the world. Potential threats and malwares are detected and monitored. They are analyzed to defend the user’s systems from the dangerous actions. Kaspersky internet security 2013, with safe money, secures keyboard and others unique features; deploy new innovative technologies that defend PCs from sophisticated threats and viruses. (Kaspersky Internet Security, 2013) Norton antivirus was developed by Symantec Corporation in 1990. Norton internet security is an effective antivirus to deal with cyber attacks and provides best internet security. Dennis technology Labs in the year of 2013 performed a comparison that included the well known tools of internet security. Norton internet security tool is included among many other good security tools. The latest versions of all tools are included for the purpose of comparison. Norton provides protection to computer from the security threats and risks. The blocking process of malicious sites is performed on the basis of the repute of particular website and this is the good approach to handle such situation. Norton is considered among best tools that provide internet security due to the enhanced features it contain (Dennis Technology Labs, 2013). Norton safeguards the computers from viruses that spread from hard disk, floppy disk as well as travel across the network and