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# Jake Soderberg - Homework 3.2 - Statistics With Excel - Dunwoody College of Technology

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### Jake Soderberg - Homework 3.2 - Statistics With Excel - Dunwoody College of Technology

1. 1. Jake Soderberg Dunwoody College of Technology QUAL 225 Statistics with Excel Sunday, February 7, 2010 HW Section 3-2, Page 145: 7, 9, 11, 13, 16, 19 Excel directions page 149 7. Police Calls in Schools, find the range, variance, stand deviation, data represents samples 7 37 3 8 48 11 6 0 Range 48.0 Variance 254.7 If the values are near the mean, the variance will be small Standard Deviation 16.0 If the values are far from the mean, the variance will be large Mean 13.3 Are the data consistent or do they vary? Explain your answer The data vaires a lot because the variance is such a large number, if the values are far from the mean, the variance will be lar 9. Percipitation and High Temperatures, find the range, variance, standard deviation, data represents samples Temperatures 50 37 29 54 30 61 47 38 Range 32.0 Variance 147.7 Standard Deviation 12.2 Taking the square root puts the standard deviation in the same units as Mean 44.1 Coefficient of Variation 27.6% CVar or the coefficient of variation allows you to compare standard dev CVar = Standard Deviation / Mean Percipitation 4.8 2.6 1.5 1.8 1.8 3.3 5.1 1.1 Range 4.00 Variance 1.88 Standard Deviation 1.37 Mean 2.63 Coefficient of Variation 52.2% Which set is more variable? The percipitation data is more variable compared to the temperature data, because the coefficient of variation (CVar) for the 11. Stories in the Tallest Buildings, find the range, variance, standard deviation, data represents samples Houston 75 71 64 56 53 55 47 55 Range 28.0 Variance 78.9 Standard Deviation 8.9 Mean 55.8
2. 2. Coefficient of Variation 15.9% Pittsburgh 64 54 40 32 46 44 42 41 Range 34.00 Variance 88.77 Standard Deviation 9.42 Mean 41.46 Coefficient of Variation 22.7% Which set of data is more variable? The Pittsburgh data is more variable compared to the Houston data, because CVar for the Pittsburgh data is a higher percenta 13. U.S. Astonaut Candidates Age, use range rule of thumb to estimate standard deviation of the applicants age Mean (age) 34 Low (age) 26 High (age) 46 Range 20 Variance 25 Variance = Standard Deviation squared Standard Deviation 5 Range rule of them is Standard Deviation = Range / 4 16. Deficient Bridges in U.S. States, find the range, variance, and standard deviation 15,458 1,055 5,008 3,598 8,984 Range 1,337 4,132 10,618 17,361 6,081 Variance 6,482 25,090 12,681 16,286 18,832 Standard Deviation 12,470 17,842 16,601 4,587 47,169 Mean 23,205 25,213 23,017 27,768 2,686 7,768 25,825 4,962 22,704 2,694 4,131 13,144 15,582 7,279 12,613 810 13,350 1,208 22,242 7,477 10,902 2,343 2,333 2,979 6,578 14,318 4,773 6,252 734 13,220 19. Cost per Load of Laundry Detergents, find the variance and standard deviation Class limits Frequency Midpoint Freq * Mid Freq * Mid^2 13 19 13-19 2 16 32 512 20 26 20-26 7 23 161 3,703 27 33 27-33 12 30 360 10,800 34 40 34-40 5 37 185 6,845 41 47 41-47 6 44 264 11,616 48 54 48-54 1 51 51 2,601 55 61 55-61 0 58 0 0 62 68 62-68 2 65 130 8,450 total freq = 35 1183 44,527
3. 3. 10 3 ance will be small ariance will be large mean, the variance will be larger presents samples 34 61 deviation in the same units as the raw data s you to compare standard deviations when the units are different 1.8 2.5 ent of variation (CVar) for the percipitation is a higher percentage 52 50 50 50 47
4. 4. 40 40 34 32 30 burgh data is a higher percentage the applicants age = Range / 4 46,435.0 87,960,224.0 9,378.7 11,595.6 Variance 133.6 Standard Deviation 11.6