Confidence Intervals and Averages
1. In a certain town, there are 25,000 families. Suppose Census data for the town
shows the true average income is $61,700 and the SD is $50,000. Estimate the
probability that a simple random sample of size 1000 has a sam
Chapter Summary
Chapter 18
Z procedures: calculating a confidence interval for the mean, as well as testing against the null
hypothesis
Mathematical Theorems are true, statistical methods are effective when used with judgement
18.1 Conditions for Inferenc
Chapter Summary
Chapter 4
4.1 Explanatory and Response Variables.

Two classifications of variables:
o Explanatory Variable: Explains or Influences the response variable. Also called
independent variables or predictor variables.
o Response Variable: Meas
Chapter Summaries
Chapter 16
This here chapters about dem dere confeedense intervuls
While we can make Statistical Inferences by using a method to draw conclusions about a population
from sample data, there are multiple types of inferences that we must ch
Chapter Summary
Chapter 15
This chapter is on the use of probability to help us define good inferences that can be made
about data about a population based on a sample.
15.1 Parameters and Statistics
Parameters are numbers that describe the Population.
St
Chapter Summary
Chapter 5
Section 5.1 Regression Lines

A regression line represents the effects that variables have with each other.
o Between explanatory variable and response variable.
The size of the slope of the regression line does not determine im
Chapter Summary
Chapter 3
3.1: Histogram to Density Curve
Characteristics of a Density Curve
o The total area underneath the curve equals 1
o Every point must have a vertical height greater than 0
o No points dip below the horizontal axis
3.2: Describing
Chapter Summaries
Chapter 22
In this chapter, were gonna move away from just looking at means and will focus on
proportions
22.1 The sample proportion pp
pp = Number of successes in the sample/ total number of individuals in the sample
pp is the sample pr
Chapter Summary
Chapter 6
6.0 A Job outside the Home
A twoway table of counts organizes data about two categorical variables.
Row variable, the category that represents the variable from the side
Column variable, the category that represents the variable
Chapter Summary
Chapter 21: Comparing Two Memes
Two Sample Problem: Inference tries to compare the response to two different treatments, or compare two
different characteristics
We also have a separate sample from each population.
21.1 TwoSample Problem
Chapter Summary
Chapter 13
13.1 Independence and the Multiplication Rule
A graphical depiction of where events A and B overlap/are not disjoint is a Venn Diagram
Independent Events are where the outcome of A does not affect the outcome of B
Multiplication
Chapter Summary
Chapter 17 Summary
Tests of inference: assesses the evidence provided by data about some claim concerning a population
parameter.
Reminder: Parameter = a metric about the whole population
17.1 The Reasoning of tests of significance
Make a
Chapter Summary
Chapter 12: Intro Probability
12.1 The Idea of Probability
Random Samples are good and all because they reduce bias, but not having enough
variability by using a low sample size can really mess things up.
As any Warhammer player knows, cha
Chapter Summary
Chapter 9 Summary: Experiments

Experiments are different than observational studies in that they gather information without
trying to disturb the population. Experiments rock the boat a bit more.
9.1 Observation versus Experiment

Exper
Chapter Summary
Chapter 8 Summary
8.0 Producing Data: Sampling
Sound Statistical Design is combining reliable sampling with practices that avoid the practical
problems of sampling from large populations.
8.1 Population Vs Sample
Population Group that we w
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Tables
Table A
Standard Normal Probabilities
Table B
Random Digits
Table C t Distribution Critical Values
Table D Chisquare Distribution Critical Values
Table E
Critical Values of the Correla
ANOVA
Analysis of Variance:
Why do these Sample Means differ as much as they do (Variance)?
Standard Error of the Mean (variance of means) depends upon
Population Variance (/n)
Why do subjects differ as much as they do from one another?
Many Random causes
Assignment 9 Solutions
2. The first option is better because there are more ways to win. Getting a king on
the first card and a queen on the second wins $1 under both options, but getting a
king on the first card and, say, and ace on the second card only
Assignment 5 Solutions
4. (a) The corresponding zvalues for 400 and 700 are (400550)/100=1.5 and
(700550)/100=1.5 respectively. To use the normal approximation, we find the area
under the normal curve between 1.5 and 1.5. From the table, we see that
Assignment 7 Solutions
2. (a) We use the regression line to estimate mean values of the dependent variable
for given values of the independent variable. In this case, the regression line is
y100 = 0.8(x100) where y represents score at age 35 and x repre
Assignment 8 Solutions
Ch. 11
3. (a) We use a regression where x is the height at age 6 and y is the height at age
18. The RMS error is
inches.
(b) We switch the meaning of the variables x and y. The RMS error is now
inches.
4. (a) Recall that about 2/3 o
Assignment 9 Solutions
2. The first option is better because there are more ways to win. Getting a king on
the first card and a queen on the second wins $1 under both options, but getting a
king on the first card and, say, and ace on the second card only
Assignment 13 Solutions
2. (a) The sample is like 500 draws from a 01 box of 25,000 tickets. The number
of 1s in the sample is the number of households with internet access. The frac tion
of 1s in the box is unknown, but is estimated by the sample fracti
Math 109 Fall 2011 Test 2 Review
(1) A study of 1,078 families produced the following statistics. Assume the scatter plot is homoscedastic.
average height of father = 68 inches SD = 2.7 inches
average height of son = 69 inches SD = 3.1 inches
correlation
1. A fair sixsided die is rolled 50 times. Estimate the probability of getting
exactly 12 sixes.
2. Suppose 33% of a certain population have O+ blood type. If a random
sample of 900 donors attend a blood drive, what is the probability that the
percent of
Significance Testing Practice Answers
First, decide which test of significance is appropriate for each problem. Then go back and answer
each question.
1. In order to test the breaking ability of two types of cars, a simple random of 64 cars of
each type w
Assignment 6 Solutions
Ch. 8
1. In graph (a), the means are too low. In graph (b), the SDs are too small. In
graph (c) the SDs are too big and the correlation is too strong. The answer is
(d).
5. (i) 0.60 a moderately strong positive correlation
(ii) 0.30
Assignment 1 Solutions
3. The parents who refused to allow their children to participate in the experiment
on the premise that the child would be exposed to a higher risk of polio were
incorrect. In the Salk trial, parents who consented were, on the whole