Download presentation

Presentation is loading. Please wait.

1
A Day of Classy Review

2
**Shifting and Scaling SAT/ACT Max SAT: 1600 (old school) Max ACT: 36**

SAT = 40 x ACT + 150 ACT Summary Stats: Lowest = 19 Mean = 27 SD = 3 Q3 = 30 Median = 28 IQR = 6 Find equivalent SAT scores

3
**SAT and ACT ACT Summary Stats: Lowest = 19 Mean = 27 SD = 3 Q3 = 30**

Median = 28 IQR = 6 SAT = 40 x ACT + 150 𝐿𝑜𝑤𝑒𝑠𝑡 𝑆𝐴𝑇 =40 ∗19+150=910 𝑀𝑒𝑎𝑛 𝑆𝐴𝑇 =40 ∗27+150=1,230 𝑆𝑡𝑎𝑛𝑑𝑎𝑟𝑑 𝐷𝑒𝑣𝑖𝑎𝑡𝑖𝑜𝑛 𝑆𝐴𝑇 =40∗3=120 𝑄3 𝑆𝐴𝑇 =40 ∗30+150=1,350 𝑀𝑒𝑑𝑖𝑎𝑛 𝑆𝐴𝑇 =40∗28+150=1,270 𝐼𝑄𝑅 𝑆𝐴𝑇 =40 ∗6=240

4
NormalCDF The NormalCDF( function finds the percent of the total area of the distribution that falls between two z-scores. For example, what would the NormalCDF(-1,1) be? (Hint: rule)

5
**NormalCDF Procedure First, determine the type of question being asked**

Once you’ve determined it is appropriate to use the NormalCDF function, convert given values into z-scores 𝑧= 𝑦− 𝑦 𝑆𝐷

6
**NormalCDF Questions: Answers:**

What percent of the distribution falls between X and Y? What percent of the distribution is greater than Y? What percent of the distribution is less than X? Answers: NormalCDF(X,Y) NormalCDF(Y,99) NormalCDF(-99,X)

7
**invNormal( Going the Other Way**

The invNormal( function finds what z-score would cut off that percent of the data Example: What z-score cuts off the top 10% in a Normal model? The bottom 20%? The trick here is figuring out what percent (as a decimal) to enter in to the function. Imagine invNormal calculates the area starting at -99. So to find the z-score that cuts off the top 10% we want the z-score that includes 90% invNormal (.9) = 1.28

8
invNormal( Example Based on the model N(1152, 84) describing angus steer weights, what are the cut-off values for A) highest 10% B) lowest 20% C) middle 40% A) invNormal(.9) = 1.28 B) invNormal(.2) = -.842 C) invNormal(.3) = -.524 invNormal(.7) = .524 1,259lbs 1,081lbs 1,108 – 1196lbs

9
**New Topic – Normal Probability Plots**

How to decide when the normal model (unimodal and symmetric) is appropriate: Draw a picture (Histogram) Draw a picture! (Normal Probability Plot) A Normal Probability Plot is a plot of Normal Scores (z-scores) on the x-axis vs the units you were measuring on the y-axis (weights, miles per gallon, etc.) A unimodal and symmetric distribution will create a straight line

10
What it Looks Like

11
What it Looks Like

12
How It Works A Normal probability plot takes each data value and plots it against the z-score you would expect that point to have if the distribution were perfectly normal These are best done on a calculator or with some other piece of technology because it can be tricky to find what values to “expect”

13
Homework Page # 3, 5, 12, 17, 28, 30

Similar presentations

OK

The Standard Normal Curve Revisited. Can you place where you are on a normal distribution at certain percentiles? 50 th percentile? Z = 0 84 th percentile?

The Standard Normal Curve Revisited. Can you place where you are on a normal distribution at certain percentiles? 50 th percentile? Z = 0 84 th percentile?

© 2017 SlidePlayer.com Inc.

All rights reserved.

Ads by Google

Ppt on mughal emperor akbar Ppt on different solid figures names Jit ppt on manufacturing software Download ppt on my role model Ppt on cleanliness of surroundings Download ppt on multimedia and animation Ppt on machine translation Ppt on e waste in india Spleen anatomy and physiology ppt on cells Ppt on indian political parties