Stat 105/Sanchez
Quiz 2
x/10
ID_
NAME_
1. The angle at which electrons are emitted in muon decay has a distribution with
density
f (x | ) =
1 + x
2
1 x 1
1 1
where x =cos . The parameter is related to polarization. Physical considerations
1
dictate that
Stat 105-Practice Midterm 2
The same rules apply to this exam as in midterm 1 (closed book, closed notes; no graphic
calculators, no phones, pen or pencil). The cheat sheet can be two-sided this time, but as
before you can only have formulas and definitio
STATS 105 Homework 5 (due Wednesday 2/18/09 in class)
Exercises 9-4, 9-10, 9-14, 9-26, 9-36, 9-38, 9-52 (data online).
9-4. The mean pull-off force of a connector depends on cure time.
a. State the null and alternative hypotheses used to demonstrate that
z-scores, and
associations
some context
Suppose you score 84 on a stats midterm.
Your friend, in another section (with a
different exam), scores 85.
Did he do better than you?
more context
Your exam: x = 75, s = 3
Friends exam: x = 85, s = 3
comparin
Means and Proportions
Two-proportions
So far, our hypothesis have compared a
sample proportion to a hypothesized
population value.
But more often, we wish to compare two
proportions to see if they are the same or
if they are different.
Example
Is obesi
STAT 105 HW2 Solutions
7-13.
a)
b)
7-19. a) Point estimate of the mean proton flux is X = 4958
b) Point estimate of the standard deviation is SX=3420
c) Estima
Homework 3 Solution
8-6
a) Sample mean from the first confidence interval =37.53 + (49.87-37.53)/2 = 43.7
Sample mean from the second confidence interval =35.59 + (51.81-35.59)/2 = 43.7
b) The 99% CI is (35.59
Homework 5 solutions
9-117
1) Interest is on the distribution of statistics and OR grades.
2) H0: Statistics grades are independent of OR grades.
3) H1: Statistics and OR grades are not independent.
4) The
Homework 6 Solution
10.87
a)
1) The parameters of interest are the proportion of satisfactory lenses, p1 and p2
2) H0 :
3) H1 :
4) Test statistic is
where
5) Reject the null hypothesis if z0 <
6)
4-6 Normal Distribution
5-5 Linear Combinations of Random Variables
1-1 The Engineering Method and
Statistical Thinking
Figure 1.1 The engineering method
1-1 The Engineering Method and
Statistical Thinking
The field of statistics deals with the collection
Cramer-Rao Inequality
Fisher Information
7-1 Introduction
The field of statistical inference consists of those
methods used to make decisions or to draw
conclusions about a population.
These methods utilize the information contained
in a sample from the
Regression
Analyzing associations between two numerical variables
Evan Ziporyn, from Bang On a Can Allstars, says this about
In C:
The piece is always recognizably itself, and yet no two
performances are ever the same.
A typical performance is about. 46 m
Does a stradivarius violin sound better
than a modern violin? (NY Times, 1/2/12:
only in people's minds.)
Can listening to music relieve pain?
Is the earth's climate growing warmer? Is
human activity to blame?
Can 8 glasses of water/day protect your
k
Numerical Summaries
measuring center &
spread
If the distribution is symmetric
the mean is a good measure of center
the standard deviation measures
variability
measuring center and
spread
But if there are outliers, or distribution is
skewed
the media
Probability
Last time
P(A and B)
P(A or B)
P(A | B)
According to the data in this sample:
If the person is a female, the
probability she is left-handed is
*
A. 226/332
Clicker question
B. 29/226
C. (226+37-29)/332
D.29/37
E. 37/226
"And"
We've seen ho
Inference with one or
two means
Outline
One mean, using computer
Hypothesis test and CI
Two means
How were data collected? Paired or
unpaired?
Review from last week
Carl Reinhold August Wunderlich
Recorded body temperatures of 25,000
people living in
Hypothesis Testing
Lecture 7.1
purpose
Confidence intervals answer the question
how much? or What percent?
Hypothesis tests answer a different type of
question: is the percentage different from
what everyone thinks it is? Or, did my
intervention change
http:/onlinestatbook.com/stat_sim/
sampling_dist/index.html
If sample is random and
independent
Sample mean is unbiased estimator of population mean.
Sample mean is a "precise" estimator, meaning that for large
sample size, there is very little variabili
Survey Sampling
Framework
We wish to estimate the proportion of all
people or objects in a population with a
certain characteristic. Call this proportion
p.
If we can survey everyone in the population,
then we have a census
But if we rely on a subset o
Inference for Means
motivating example
What would you say is a healthy body
temperature (in Fahrenheit)?
98.6 degrees F.
This figure comes from data collected in.
the 1840s
Carl Reinhold August Wunderlich
Recorded body temperatures of 25,000
people li
Numerical Summaries
Does political affiliation
vary with gender in our
class?
What's gender
distribution in class?
about 68% female
What's political
distribution?
If gender and political affiliation are not related, then we
should see about 68% females in
Example questions
The distribution of womens heights follows a
normal model with mean 64 inches and
standard deviation 3 inches. What percent of
women are.
A) taller than 65 inches
B) Between 60 and 66 inches?
C) If a womans height is in the 90th percent
On midterm
Interpreting intercept and slope WILL be
covered (modestly) on the midterm.
expect one or two multiple choice
questions checking to see if you can
determine which interpretation is valid.
Last Time
Regression line is the line that provides t
Welcome to Stats 10
Tyson Roberts
Fall, 2015
Today
Classroom logistics
Introduction to Data
Course information
http:/ccle.ucla.edu
Tyson Roberts: MS 8145
[email protected]
Office Hours: M 10-12 (and usually right
after class W&F)
Required Mater
Paired and Independent Samples
A study to test the effectiveness of diet: researchers
randomly assigned 168 overweight people to one of four
diets: Atkins, Weight Watchers, Ornish, The Zone
Weight was measured before starting, and 12 months
later.
kilogra
Outline
What's a distribution of a variable in a
sample?
Pictures of distributions: center, spread,
shape.
Numerical summaries of distributions:
center & spread.
Distribution
One of the fundamental concepts of
statistics.
Used to organize data in a s
9-1 Hypothesis Testing
9-1.1 Statistical Hypotheses
Statistical hypothesis testing and confidence interval
estimation of parameters are the fundamental methods
used at the data analysis stage of a comparative
experiment, in which the engineer is intereste