Nine weird tips for - PowerPoint Presentation

Slide1

Nine weird tips for

adding

to level 2 and 3 Stats

Michael

Shadbolt

Otumoetai

College

mshadbolt@otc.school.nzSlide2

Introduction

Otumoetai

College, State Co-ed in Tauranga. 2000 students. 2IC Math Dept. 8 years teaching.

L3

Statistics for most of that.

Standards

realignment

, full

L2

Statistics

course

(no

standards in common with our L2 Math

course.)

As

a result, we now have

five L3

Statistics

classes

, without taking numbers away from the three L3

Calculus

classes

.Slide3

Q1. Why can incorrect Bivariate analysis kill puppies?Slide4

Puppy Lives? You Decide!

It’s not always obvious which variable is the response and which is the explanatory. Sometimes we need to think about which one makes more sense as an

explanatory.Eg: Heart weights of puppies vs body weights of puppies.

Do we want to be able to predict a puppy’s body weight by cutting out

its

heart and weighing it?

Or do we want to be able to predict a puppy’s heart weight by weighing the whole puppy?

In

this case, perhaps it would be better if heart weight was

response

and

body

weightwas explanatory…

I ruff you!Slide5

Q2. Why is freeze-dried ice-cream better than cornflakes?Slide6

Continuity Correction

Question: The weight of boxes of

“Kellogg’s

Kream

Krunch

” are normally distributed with a mean of 760g and a standard deviation of 5g. If the weight of the boxes is recorded

to the nearest gram

, find the probability that a box of “

Kream

Krunch

” is recorded as at least 750g.

Answer: If the box is to be recorded as at least 750g, the actual box must exceed 749.5g

Thus P(X

≥ 750)

= P(X > 749.5)

(continuity correction)

= 0.98213(note: without continuity correction, the answer would have been 0.97724)

750gSlide7

Q3. Why is

goody-gumdropice-cream "poissonous"?Slide8

You Scream, I Scream…

You will be given a scoop of

gumdrop ice cream.

Eat it and count the number of pieces of gumdrop you get.

The random variable X will be the number of pieces of gumdrop per scoop of ice cream. Slide9
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Q4. Why is Yoda a fan of

Venn Diagrams?Slide11

P(Try

′) = 1P(Do) = 0.7P(Do′) = 0.3

 P(Try) = Ø

P(Do)

0.7

0.3

?

P(Try)Slide12
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Q5. Am I going to die from

a meteor strike?Slide19
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Meteor To Hit Earth!

A meteor is going to hit Earth! We want to know the probability that it hits land, as opposed to landing in the ocean.Why would we simulate this? (Why not do an actual experiment?)What tool could we use to simulate this?What assumptions are we making?How will we calculate the probability that a meteor would land on… well, land?Slide21

Q6. Am I going to die from

a lightning strike?Slide22

Fire Island AssessmentSlide23
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Sample of simulation outcomes (km

2

lost)Slide25
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Q7. Am I going to die from

falling asleep?Slide27

Results from wearing a heart-rate monitor overnight. X-axis is time (seconds) after going to bed. Y-axis is heart rate in beats per minute.

Describe the overall trend. What would happen to Tim (the person monitored) if he kept sleeping? Make an approximate forecast for Tim’s heart-rate after 24hrs asleep.Slide28

Source: xkcd.comSlide29

Q8. Is Frane

Selak the unluckiest man to ever live?Slide30
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Q9. Are polar bears really stealing our money

?Slide33
Slide34

Area Bias Example:Polar Bear Population

The World Wildlife Fund (WWF) has written on the threats posed to polar bears by global warmingHowever, also according to them, about 20 distinct polar bear populations exist accounting for approximately 22,000 polar bears worldwide.Only 2 of the groups are decreasing10 populations are stable2 populations are increasingThe status of the remaining 6 populations is unknownIf you are only looking at the 2 groups that are decreasing, it would be easy to say that the “Polar Bear Population is Decreasing”. You need to look at the whole picture to get the whole storySlide35