Recall from Ch14:
Let X and Y be independent random variables. Then X Y is a random variable and
Var ( X Y ) VarX VarY and SD( X Y ) VarX VarY
Suppose we are interested in if there i
The following lab is to give you a chance to generate your own graphs and statistics using software.
Paste your graphs and statistics on this word document, use these graphs and statistics to answer a few questions, and then
Simply put, learning statistics can help
us: think more clearly about data
2. In this course, we will be working with
only those questions that can be
answered by statistics
3. What three things will we do as data
investigators? Examine the Question,
STA2023 Worksheet #1
The following problems come directly from the assigned homework.
They are due on the day of the test.
If you have been keeping up with the homework all along, feel free to just turn in all of
the homework together. I will go through i
More about Tests and Intervals
Alpha Levels (significance levels) denoted -level
An -level is a threshold for the P-value that is set before the experiment is done.
If P-value < -level, reject H 0 .
If P-value -level, fail to
Paired Samples and Blocks
Data are paired when the observations are collected in pairs or the observations of one group are naturally
related to the observations in the other group.
The simplest form of pairing i
Inferences about Means
Recall: CLT (for sample Means)
When a random sample is drawn from any population with mean
and standard deviation
x , has a sampling distribution that is approximately normal with x
Confidence Intervals for Proportions
Suppose you take a random sample of 100 U.S. adults and find that 56% of your sample believes in
ghosts. What can you say about the proportion of all U.S. adults who believe in g
Sampling Distribution Models (sample proportions and sample means) Sections15.1-15.5
Suppose we take a random sample of 100 people and find that 10% are left-handed.
We take another random sample of 100 people and find th
Testing Hypothesis about Proportions
National data in the 1960s showed that about 44% of the adult population had never smoked cigarettes. In
2008 a national health survey interviewed a random sample of 600 adults and
Chapter 5 Probability
Section 5.1 - Probability Rules
Probability The quantitative (numerical) measure of something occurring.
There are 2 types of probability that we will examine:
Empirical probability Probability is measured by using the result