Name
Student #
STAT 101
Midterm Examination: Key
Richard Lockhart
Instructions:
22 February 2012
1. This is an open book exam; you may use your text or another text and any notes you
wish to bring.
2. You may use a calculator (with no wireless communicati
Summary of Bivariate Descriptive
Statistics
Relationship between two quantitative
variables
Scatterplot: dot (,) <-> individual
: the value of the variable for -axis
: the value of the variable for -axis
Summary of Bivariate Descriptive
Statistics
Ov
Explore
explanatoryresponse
relationship
Vocabularies - Explanatory
Variables
Factors: the explanatory variables
Examples: plant several different types of wheat
in different fields. Use different amounts of
fertilizer on different fields.
Two factors
Univariate Descriptive
Statistics
Data
Explorative
Data
Analysis
Graphs and Numbers
Bivariate Descriptive
Statistics
Purpose is unrestricted exploration of the data,
searching for interesting patterns.
Conclusions apply only to the individuals and
circums
A diagnostic test for a certain disease
We expect its false positive rate is low.
False positive: if the test result for an
individual who does not have the disease
is positive.
Question: what is the false positive rate in
all the individuals who do n
Back to Example
Experiment: toss a fair coin twice
S = cfw_HH, HT, TH, TT
assign 1/4 to each possible outcome
X = the number of heads occur
All possible values of X: 0, 1, 2
Values
0
1
2
Probability
1/4
1/2
1/4
Binomial Setting
A binomial setting ar
Statistical Inference
Point estimation: use the sample mean xx to estimate the
population mean .
The law of large numbers ensures us that if we measure
enough subjects, the sample mean will eventually get
close to the population mean.
xx is an unbiased
Probability Model
A probability model for a random
phenomenon consists of a sample space S
and an assignment of probabilities P.
Finite Probability Models
A finite (fixed and limited) number of
outcomes.
Binomial probability models.
A probability mode
Correlation does not depend on which variable
you put on x axis and which on the y axis
Often, interests lie on whether or not changes
in x variable help explain changes in y variable
x variable: explanatory variable
explain or influence changes in y
Stat 101 - Assignment # 3
Deadline: 4:00pm October 17th, 2013
Please drop your assignment to the assignment-dropping box. It is located right
outside the Stat Workshop (K9510). Please drop before the deadline. We will not
accept any assignment after the d
Chapter 8 Producing Data: Sampling
-a sample survey selects a sample from the population of all individuals about which we desire information. We base conclusions about the
population on data from the sample. It is important to specify exactly what popula
Solutions
1.2
STAT 101 - Assignment 1 - Solutions
Answers will vary. Some possible categorical variables: Whether or not student plays on a
sport team or with a club; Sex; Whether or not the student smokes; Attitude about exercise,
etc. Some possible quan
1. From a list of five 1's, ten 2's, and eight 3's (so that the list is 23 numbers long),
find the average and standard deviation.
2. For all the people in Canada (including children), which is likely to be larger, the
average height or the median height?
Assignment 2
Rishi Dholliwar
5.30
Page 154
a) The slope of the regression line is 0.0138. The response variable is dive duration and response
is the depth, so the slope is the amount by which dive duration changes when the depth is
increased. In other wor
STAT 101 - Assignment 2 - Solutions
Solutions
5.30
5.32
Penguins Diving
7
Duration (minutes)
(a) The slope is 0.0138 minutes per meter. On
the average, if the depth of the dive is
increased by one meter, it adds 0.0138 minutes
(about 0.83 seconds) to the
Name
Student #
STAT101
Midterm Examination: Key
Richard Lockhart
Instructions:
22 February 2012
1. This is an open book exam; you may use your text or another text and any notes you
wish to bring.
2. You may use a calculator (with no wireless communicatio
What if is unknown?
Recall the setting where the population distribution is
Normal with unknown mean and known SD .
We use the sampling distribution of x
Then the distribution of
is the standard Normal distribution N(0,1). This is
called the z sta
12.38
Of the seven cards, there are three 9s, two red 9s, and two 7s. (a). P (draw a 9) = 3/7
(b). P(draw a red 9) = 2/7 (c). P(dont draw a 7) = 1- P(draw a 7) = 1 2/7 = 5/7
12.42
(a). It is
5.30 (a) The slope is 0.0138 minutes per meter. On the average, if the depth of the
dive is increased by one meter, it adds 0.0138 minutes to the time spent
underwater.
(b) When D = 200, the regression formula estimates DD to be 5.45 minutes.
( c) To plot