lecture 9 - ECMT1010 Business and Economic Statistics A(semester 2 2013 Lecturer Simon Kwok Statistics Unlocking the Power of Data Lock5 Announcements

# lecture 9 - ECMT1010 Business and Economic Statistics...

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Statistics: Unlocking the Power of Data Lock 5 ECMT1010: Business and Economic Statistics A (semester 2, 2013) Lecturer: Simon Kwok
Statistics: Unlocking the Power of Data Lock 5 Announcements Online homework 7: due at 5pm tomorrow (this Wednesday). Online homework 8: to be released after 1pm on 10 October (this Thursday).
Statistics: Unlocking the Power of Data Lock 5 Outline Density curves (Section 5.1) Normal distribution (Section 5.1) Finding normal probabilities (technology) Finding normal endpoints (technology) Standard normal Central limit theorem (Section 5.2) Confidence interval using a normal distribution Hypothesis test using a normal distribution
Statistics: Unlocking the Power of Data Lock 5 Some Bootstrap and Randomization Distributions slope ( thousandths ) -60 -40 -20 0 20 40 60 Dot Plot r -0.4 -0.2 0.0 0.2 0.4 0.6 Nullxbar 98.2 98.3 98.4 98.5 98.6 98.7 98.8 98.9 99.0 Diff -4 -3 -2 -1 0 1 2 3 4 xbar 26 27 28 29 30 31 32 Dot Plot Slope :Restaurant tips Correlation: Malevolent uniforms Mean :Body Temperatures Diff means: Finger taps Mean : Atlanta commutes phat 0.3 0.4 0.5 0.6 0.7 0.8 Proportion : Owners/dogs All bell-shaped distributions
Statistics: Unlocking the Power of Data Lock 5 Density Curve A density curve is a theoretical model to describe a variable’s distribution. Think of a density curve as an idealized histogram, where: (1) The total area under the curve is one. (2) The proportion of the population in any interval is the area over that interval.
5 Density for Bootstrap Means for Atlanta Commutes What proportion are between 30 and 31?
Statistics: Unlocking the Power of Data Lock 5 Normal Distribution A normal distribution has a symmetric bell-shaped density curve.