Review
Last day we started Chapter 4:
The idea of probability
Estimating a probability from a sample
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Conditions for Inference About a Mean
1
Conditions for Inference about a Population Mean
Random: The data come from a random sample of size n from the
population of interest or a randomized experiment.
Normal: The population has a Normal distribution. I
The Practice of Statistics for
Business and Economics
Third Edition
David S. Moore
George P. McCabe
Layth C. Alwan
Bruce A. Craig
William M. Duckworth
2011 W.H. Freeman and Company
Introduction to Inference
Estimating with Confidence
PSBE Chapter 6.1
20
Review
We talked about the general types of variables, note that your
textbook covers other variables, but I wont test you on those.
Just be aware that there are other types of variables.
Categorical and Quantitative variables
Categorical variables: Ordin
Review
Last day we finished Section 4.2:
Probability Rules
Probability Rules in Mathematical Notation
Discrete Probability Models
Continuous Probability Models
Use the Standard Normal Curve (and Table A) to find
probabilites
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Review
Last day we looked at:
Transformations for data that is not linear
Correlation does not imply causation!
Assessing the fit of a regression line
R2
Residual plot
Influential observations
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Review
Think back to the day before the break.
Population, Sample, Sampling Design
Response Rates
Bias-Bad Sampling
Simple Random Sampling (SRS)
Other Good Sampling:
Stratified Random Sampling
Multistage Sampling
Table of Random Digits (Table B)
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The Lab
I hope everyone had fun in the lab yesterday! I am so impressed
with everyone! I will have a look at everyones answers and send
an email back if there was something I notice. The goal of the
assignment question is:
Figure out what the question is
The Lab
I was finally able to get the lab question working through Connect.
Some comments:
The question you get is randomly assigned out of a group of
10 possible questions. These 10 questions are listed at the end
of your lab.
It is a good idea to work t
Review
Last day we finished up Chapter 1 and moved on to Chapter 2:
We saw that given a proportion or percentage we can find the
cuto value for that percentage
We had a look at the Normal Quantile plot, just remember
that it exists!
We looked at the Respo
Review
Way, way, way back before the Midterm and Midterm review.
Probability Rules continued
And vs. Or?
Independent vs. Disjoint
General Probability Rules
General Addtion Rule P(A OR B)
General Multiplication Rule P(A AND B)
Conditional Probability P(B G
Updates!
I can finally log in to my ocial email:
emelie.gustafsson@ubc.ca
I have oce hours: the hourish before class, but if I am in my
oce you are welcome to stop by with questions.
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Table of Random Digits
We have many dierent options for picking an SRS. The most
old-school but also my preferred way is to use a table of random
digits. (Table B) A table of random digits is a long string of the
digits 0,1,2,3,4,5,6,7,8,9 with these two
Updates!
I have an oce! SCI 104
I have an ocial email: emelie.gustafsson@ubc.ca
I have access to Connect and I think I have uploaded the
lecture notes and lab. Let me know if I havent.
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Review
Last day we had our quiz which covered:
Confidence intervals for one sample with known.
Hypothesis testing for one sample with known.
Confidence intervals for one sample with unknown.
Hypothesis testing for one sample with unknown.
Confidence inter
Review
Last day we talked about Confidence Intervals (CIs):
The idea behind CIs is to give some bounds on our sample
mean that we are confident (to some confidence level) will
capture the true population mean.
The population mean is a fixed number that we
V1
V2
V3
V4
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R_26lNwfADefault Re Anonymous
R_42QmrtUDefault Re Anonymous
R_etgn0Tf Default Re Anonymous
R_1G1DqxNDefault Re Anonymous
R_8FU56KUDefault Re Anonymous
R_56CA4n2Default Re Anonymous
R_b2UwhrRDefault Re Anonymous
R_3
Stat 124
Assignment 6 (Last One!)
(7.73*, 7.74, 7.78*, 7.92, 7.94*, 7.123) *=Revised
[Q1]. 7.73 Comparison of blood lipid levels in males and females. Coronary heart
disease (CHD) begins in young adulthood and is the fifth leading cause of death among adu
Quiz 2
Name:
St udent Number:
This exam includes 4 questions. The total number of points is 35. You
MUST show all your work for full marks. Please do not write on the
tables since we still need them for the Final Exam.
Question 1 (10 points)
The platypn
Quiz 2
Name:
Student Number:
This exam includes 4 questions. The total number of points is 35. You
MUST show all yolu~ work for full marks. Please do not write on the
tables since we still need them for the Final Exam.
Question 1 (10 points)
The platypl
Lab 10
Stat 124
Condence Intervals and Hypothesis Testing for Two Independent Samples
1
t-Tests for Two Independent Samples
We looked at the t.test function for one sample and for paired samples in the last lab, you wont be surprised to
know that the same
Lab 9
Stat 124
Condence Intervals and Hypothesis Testing
1
t-Tests in R
We know that when we dont know we must use a t-test instead of a z-test to test our hypotheses, and a
t* instead of a z* in our condence intervals. The real question is, how do we mak
Lab 8
Stat 124
Condence Intervals and Hypothesis Testing
Now that you know what condence intervals are and what hypothesis testing is, it is time to see how we can
make R do the work for us! As I have mentioned a few times, the assumption that we know the
Stat 124 Lab 71
Investigating the Central Limit Theorem
The Central Limit Theorem (CLT) states three facts about the statistics of sample means. Remember what
we are doing in general: Given a population, we take samples of size n and from these samples we