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 Sujet: analysis
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 A pie chart 2016-12-05 vickie pose la question :Determine the central angle needed to form a pie chart for the following housing characteristic data: 63% owner occupied, 27% renter occupied, and 10% vacantPenny Nom lui répond. Broken-line graphs and histograms 2006-02-16 George pose la question :1. What is the main difference between a broken-line graph and a histogram? Both represent continuous variables. 2. What is the correct way to read a multiplication array: x-axis first and then y-axis, other way around or it doesn't matter? Penny Nom lui répond. A normal distribution problem 2006-02-15 Mary pose la question :In a certain normal distribution, find the mean when the standard deviation is 5 and 5.48% of the area lies to the left of 78.Penny Nom lui répond. The median 2006-01-27 Wael pose la question :" median"; what does it mean and how do we calculate it?Penny Nom lui répond. Coefficient of variation 2005-10-19 Jan pose la question :I am currently teaching the coefficient of variation and am wondering if there are some guidelines as to the interpretation of this statistic. I understand that it measures the variation in a variable relative to the mean - but what is the cut off for "too much" variation expressed in this way??? Andrei Volodin and Penny Nom lui répond. Linear regression 2002-01-16 Murray pose la question :If you have a set of coordinates (x[1],y[1]),(x[2],y[2]),...,(x[n],y[n]),find the value of m and b for which SIGMA[from 1 to m=n]AbsoluteValue(y[m]-m*x[m]-b) is at its absolute minimum.Harley Weston lui répond. Dual spaces 2001-11-26 Hoda pose la question : In the book "Linear Functional Analysis" from Epstein there is a proof (page 116) of the following theorem: The dual space of Lp is equal to Lq. Later, it is stated as a theorem without proof that for 1 <= p < +infinite, The dual space of lp is equal to lq. Doug Farenick lui répond. Box and Whisker plots 2001-11-19 Rod pose la question :In our Prealgebra course, we have been studying Box and Whisker plots. Recently, we learned how to decide whether a data point is an outlier or not. The book (Math Thematics, McDougall Littell) gave a process by which we find the interquartile range, then multiply by 1.5. We add this number to the upper quartile, and any points above this are considered to be outliers. We also subtract the number from the lower quartile for the same effect. My question: where does this 1.5 originate? Is this the standard for locating outliers, or can we choose any number (that seems reasonable, like 2 or 1.8 for example) to multiply with the Interquartile range? If it is a standard, were outliers simply defined via this process, or did statisticians use empirical evidence to suggest that 1.5 is somehow optimal for deciding whether data points are valid or not? Penny Nom lui répond. e^pi > pi^e 2001-07-27 Dusty pose la question :What book(s) contain a proof that ePi > Pie? I think it might be in Problems in Analysis published by Springer-Verlag but I have not been able to check.Chris Fisher lui répond. A confidence interval 2001-06-28 Murray pose la question :An investigator wants to find out of there are any difference in "skills" between full and part time students. Records show the following: ```Student Mean Score Std Dev Number ---------- ----------------- ---------- ----------- Full time 83 12 45 Part time 70 15 55 ``` Compute a 95% confidence interval for the difference in mean scores.Andrei Volodin lui répond. What is the difference between Mean and Average? 2000-12-13 Julie pose la question :What is the difference between Mean and Average? My thinking is the average, is the equal to the sum of all numbers divided by the number of numbers added together. But the mean, I think should be calculated by adding the largest and smallest numbers in the set and them dividing by 2. (which is the point where 1/2 the numbers are higher and 1/2 the numbers are lower)Patrick Maidorn and Penny Nom lui répond. Mode 2000-09-22 James Barton pose la question :I have always been told that a mode is the "one" number that appears most in the set of numbers: ex.{1,3,4,6,3,2} the mode is 3. What if you have {1,1,3,4,5,5}is there a mode. I was taught long ago that there is no mode, Not i am having to teach there is two modes. 1 and 5. If this is the case if we have {1,1,2,2,3,3,4,4,5,5} that every number is the mode. True or false. This is being ambigiuous if we say all are the mode. Because no one number is used more than the others.Claue Tardif and Harley Weston lui répond. Central Limit Theorem and Law of Large Numbers 2000-06-26 Jonathan Yam pose la question :The Central limit Theorem states that when sample size tends to infinity, the sample mean will be normally distributed. The Law of Large Number states that when sample size tends to infinity, the sample mean equals to population mean. Is the two statements contradictory?Paul Betts and Harley Weston lui répond. Sample variance 2000-04-16 Jonathan Freeman pose la question :I was just reading your article entitled "A Note on Standard Deviation" I'm now teaching a unit on s.d. and my students were wondering why one uses a denominator of n for a population and n-1 for a sample. I saw in your article that this is because "[the quantity] tends to underestimate sigma... and other technical reasons." To which my students again asked... "Why?" Could you please elaborate a bit on the "other technical reasons" perhaps in terms a high school senior (or their teacher...) could understand?Harley Weston lui répond. Estimating the population mean 1999-11-13 John Barekman pose la question :Statitistics: Estimating the population mean when the standard deviation is known: I am not sure which n to use in the formula for the confidence interval equation: x +/- z*(standard deviation/sqrt(n)) If we have data of ten people, and if we have the data of ten sets of ten people each, what is the difference in the n that we use? What is the difference between the standard deviation and the standard error? Are we using the number of sampling means or just the number of samples?Harley Weston lui répond. Stem and Leaf Plot 1999-09-14 Jeanette Sovick pose la question :My 5th grade son brought home a math paper, the title of which reads, Reading Stem-and-Leaf Plots...can you explain this so I can explain it to him...There is no book, his teacher just sent this practice sheet home for him to complete and I have no clue!Penny Nom lui répond.

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