Commit c1ee67ff by Robert Ricci

### Copy in working notes

parent 545b87f9
 Execution time: Normally distributed - mean 5 seconds, sttdev 1 second > dnorm: density, pnorm: distribution, qnorm: quantile All: x, mean=, sd= dnorm(5,mean=5,sd=1) x <- seq(0, 10, by=.1) plot(x,dnorm(x, mean=5, sd=1)) plot(x,pnorm(x, mean=5, sd=1)) XXX draw area under curve XXX plot lines default? Part A: probability of being more than 8s pnorm(8, mean = 5, sd = 1) tells you prob of being 8 or less, so 1 - Don't forget, probabilty, not percent Part B: probability of being less than 6s pnorm(6, mean = 5, sd = 1) Part C: prob of being between 4 and 7 pnorm(7, mean = 5, sd = 1) - pnorm(4, mean = 5, sd = 1) Part D: 95th percentile execution time Inverting the PDF qnorm(0.95, mean = 5, sd = 1) > x = seq(0,1,by = 0.01) > plot(x,qnorm(x,5,1)) Question 5: D <- c(9, 11, 13, 14, 15, 15, 16, 19, 21, 23, 23, 23, 23, 24, 24, 25, 28, 28, 29, 31, 33, 33, 34, 34, 34, 35, 35, 36, 36, 38, 39, 42, 45) A 10th and 90th percentiles D[as.integer(length(D)*.10)] D[as.integer(length(D)*.90)] quantile(D,.90) B mean mean(D) C 90% ci mean(D) - (qnorm(.95)*sd(D))/sqrt(10) D What fraction less than 25, and what is 90% CI for the fraction XXX E One-sided confidence interval 90% Question 6: c = concatenate > A <- c(140, 120, 176, 288, 992, 144, 2736, 2796, 752, 17720, 96) > B <- c(98, 120, 141, 317, 893, 86, 1642, 1678, 376, 8860, 67) > D <- A - B > mean(A) > mean(B) > mean(D) X +- z*s / sqrt(n) z_1-2/alpha XXX / 2 XXX paired XXX nonpaired > plot(x,mean(D) - (qnorm(x)*sd(D))/sqrt(10), type='l', > ylim=c(-1000,3000)) > lines(x,mean(D) + (qnorm(x)*sd(D))/sqrt(10)) mean(D) - (qnorm(0.9)*sd(D))/sqrt(10) mean(D) + (qnorm(0.9)*sd(D))/sqrt(10) (really 80%) XXX diff
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