Chapter 4, part 2
Brad McNeney
20170314
Load packages
library(car)
library(broom)
library(ggplot2)
library(dplyr)
library(gapminder)
data(gapminder)
Topics
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Exploratory data analysis
Checking model assumptions
Identifying unusual points
Present a
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A new surgical method is proposed to benefit Parkinsons patients.
To accurately test the effectiveness of the surgery, we should use a placebocontrolled
randomized doubleblinded clinical trial.
Heartattack:
Aspirin vs.
Clinical Trial 
hum
13
Density curves
Describing density curves
Normal distributions
The 689599.7 rule
The standard Normal distribution
Finding Normal proportions
Using the standard Normal table
Finding a value given a proportion
Normal Distribution
Histogram stem
Histogram & Stemplot
Pie Charts and Bar Graphs
Field of Study
Field
Percent of students
Arts and humanities
10.6
Biological sciences
14.7
Business
14.5
Education
5.2
Engineering
11.2
Health professions
12.8
Math and computer science
3.7
Physical sciences
Chapter 17 Solutions
17.1. All of the outcomes are equally probable if the coin is fair because heads and tails are
equally likely. Thus, all sequences of 10 particular outcomes are equally likely.
17.2. A correct statement might be, If you tossed a coin
13
Density curves
Describing density curves
Normal distributions
The 689599.7 rule
The standard Normal distribution
Finding Normal proportions
Using the standard Normal table
Finding a value given a proportion
Normal Distribution
Histogram stemp
Histogram & Stemplot
Pie Charts and Bar Graphs
Field of Study
Field
Percent of students
Arts and humanities
10.6
Biological sciences
14.7
Business
14.5
Education
5.2
Engineering
11.2
Health professions
12.8
Math and computer science
3.7
Physical sciences
IQ test scores. Figure 13.13 is a stemplot of the IQ test scores of 74 seventhgrade students. This
distribution is very close to Normal with mean 111 and standard deviation 11. It includes all the
seventhgraders in a rural Midwest school except for four
6.8 Magic mushrooms.
A Washington Post article reported that psilocybin, the active ingredient of magic mushrooms,
promoted a mystical experience in two thirds of people who took it for the first time, according to a
study published in the online journal
13.12 Between what values do the IQ scores of 68% of all rural Midwest seventh graders lie?
68% of the observations fall within one standard deviation of the mean.The mean is 111, the
standard deviation is 11, thus the IQ scores of 68% of all rural Midwes
STAT 100Assignment # 2 Solutions (Total 25 marks)
6.8.
Double blind means that neither the subjects nor the experimenters know who is
getting which treatment; this method prevents the researchers expectations from the
affecting the way in which the subjec
Stat 1112
11.8 Lightning storms.
Figure 11.10 comes from a study of lightning storms in Colorado. It shows the distribution of the
hour of the day during which the first lightning flash for that day occurred. Describe the shape,
center, and variability o
Review and Practice Exam Questions for Exam 2
Learning Objectives:
Chapter 17: Thinking about chance
Explain how random events behave in the short run and in the long run and how random and
haphazard are not the same thing.
Perform basic probability calcu
Review Questions for Midterm Part 3
Chapter 17
1. If I toss a fair coin five times and the outcomes are TTTTT, then the probability that
tails appears on the next toss is
A) 0.5. B) less than 0.5. C) greater than 0.5. D) 0. E) 1.
Ans: A
2. If I toss a fai
Scores on the 2007 SAT writing exam were normally distributed, with mean 495 and standard deviation about 110. Question number 1 to 3.
1. The median score was
A) 110. B) 715. C) 495.
D) Can't be determined without more information.
2. What percent of all
STAT 100 Assignment # 3
Due Friday 10th March by 3.00 pm
1. Text Book Question 13.12
2. Text Book Question 13.14
3. Text Book Question 13.18
4. Text Book Question 13.22
5. Text Book Question 13.24
6. Text Book Question 14.28
7. Text Book Question 15.18
8.
STAT 100: Chapter 1
Where Do Data Come From ?
Statistics: The science of data.
We gain insight and make conclusions based on data.
Principles We Will Study:
1. What is a good design of an experiment?
2. How should samples be gathered?
3. What are the be
STAT 100: Chapter 14
Describing Relationships:
Scatterplots and Correlation
Example: Consider the population of cars manufactured in the U.S.
What is the relationship (1) between engine size and horsepower?
(2) Between engine size and gas mileage?
Do ca
STAT 100: Chapter 18
Probability Models
Example 1: If we pick a person at random, what are the possible blood
types of that person? Which blood type is the likeliest?
A probability model presents a probability distribution for some
random phenomenon.
I
STAT 100: Chapter 20
Expected Values
Example 1: A campus organization is holding a raffle to raise
money.
There are two prizes: a $200 gift certificate to the campus
bookstore,
and a $50 gift certificate.
1000 raffle tickets will be sold (at $1 a piece)
STAT 100: Chapter 17
Chance Behavior in the Real World
Example 1: In football, the decision of which team receives
possession first is based on a coin toss.
We say the probability of a coin toss coming up heads is
0.5.
This means if we toss the coin ma
STAT 100: Chapter 15
Describing Relationships:
Regression, Prediction and Causation
Example 1: Could we predict or explain a states Democratic vote
% in the 2008 election based on its Democratic vote % in the 2004
election?
Scatterplot shows a positive
Introduction to Statistics for the Social Sciences
STAT 203

Fall 2015
Samuel Choi 301310974 (worked with Leo Li)
Statistics 203
Feb 1st 2017
Stat 203 Assignment 2
9.32
a) The explanatory variable is how much exercise a person got and the response
variable is how much efficient and long each persons sleep cycle was.
b) Subje
Introduction to Statistics for the Social Sciences
STAT 203

Fall 2015
Samuel Choi 301310974 (worked with Leo Li)
Statistics 203
Jan 20th 2017
4.28
a) The response and explanatory variables of new adults and percentage of returning birds have a
negative correlation and is linear. Correlation r is an appropriate measure of th
Introduction to Statistics for the Social Sciences
STAT 203

Fall 2015
Samuel Choi 301310974 (worked with Leo Li)
Statistics 203
Jan 20th 2017
1.30
The distribution is nonsymmetric and skewed to the right; positively skewed. The center
of the distribution is at 2 servings of fruit per day.
Range = 15  3 = 12
Q2=2(median)
Q
Introduction to Statistics for the Social Sciences
STAT 203

Fall 2015
Samuel Choi 301310974 (worked with Leo Li)
Statistics 203
Feb 1st 2017
Stat 203 Assignment 2
8.32
a) The poll has in mind the adults of each household usually 4050 years of age that
watches movies of any frequency.
b) 2000831=1169 the nonresponse rate i
Introduction to Statistics for the Social Sciences
STAT 203

Fall 2015
Samuel Choi 301310974 (worked with Leo Li)
Statistics 203
Jan 20th 2017
2.31
a) This data distribution of guinea pig survival times is rightskewed with the median
around 100 days, and range from about 0600.
b) Since the data is strongly rightskewed, I
Introduction to Statistics for the Social Sciences
STAT 203

Fall 2015
Samuel Choi 301310974 (worked with Leo Li)
Statistics 203
Jan 20th 2017
2.32
a) We prefer a histogram of the percentages rather than using the frequency as it can
get confusing where the data is concentrated when comparing two different data sets
with dif
Introduction to Statistics for the Social Sciences
STAT 203

Fall 2015
Samuel Choi 301310974 (worked with Leo Li)
Statistics 203
Feb 1st 2017
Stat 203 Assignment 2
8.36
The bias shown is probably from the fact that people are not completely transparent
when answering questions that have a relation to the law. Not having a se