Stats 8 (Baldi) Practice Midterm 1
Problem 1
You want to study the relationship between the weight of a mother dog (in pounds) and the size
of the litter of pups she delivers. You have the following data:
Weight of mother (in pounds)
Number of pups in lit
Stats 8 (Baldi) Practice Midterm 1 ANSWERS
Problem 1
You want to study the relationship between the weight of a mother dog (in pounds) and the size of
the litter of pups she delivers. You have the following data:
Weight of mother (in pounds)
Number of pup
Practice final exam STATS 8 ANSWERS
For each study described in questions 1 through 6, select the appropriate inference procedure.
1. A study collects data on the serum immunoglobulin IgM concentration of a random sample of
298 preschoolers in order to es
Practice final exam STATS 8
For each study described in questions 1 through 6, select the appropriate inference procedure.
1. A study collects data on the serum immunoglobulin IgM concentration of a random sample of
298 preschoolers in order to estimate t
Inference review
PSLS chapters 14,15, 17,18, 22, and 24
Copyright Dr Brigitte Baldi 2017
Understanding statistical conclusions
Statistics is a methodology based on probability theory.
You can never be absolutely certain of your conclusions.
You can never
Continuous random variables
Continuous sample spaces contain an infinite number of outcomes
over an interval of values.
Normal distributions
We use mathematical functions
called density curves to model
continuous probability distributions.
PSLS chapter 11
Standard deviation s - standard error of the mean s/n
The sample standard deviation is noted by the symbol s
Inference for a population mean
The standard error of the mean, SEM, is the value
( unknown)
s
n = SEM
The standard error of a statistic is the es
Stats 8 fall 2016 (Baldi) FINAL
Name: _Student ID: _
Keep your eyes on your own work. No electronic devices are allowed except for your graphing calculator.
Cheating will be reported to UCI and result in a grade penalty at the instructors discretion (incl
STAT 8
Homework 3 Solutions
Show work.
1. You are to model the daytime temperature of the Mojave desert during the summer time. Based
on records, temperatures in the desert are modeled to follow a normal distribution with mean
= 102 Fahrenheit and varian
STAT 8
Homework 2 Solutions
1. Below is the probability distribution table of the number of limbs (out of 4) that are injured in
a car accident.
x
P(X=x)
0
0.40
1
0.20
2
0.20
3
0.10
4
0.10
a. Check that this table is a legitimate probability distribution
STAT 8
Final Practice Solution
1. An insurance company wants to investigate if the average amount of a claim is above $2500.
They take a random sample of 144 claims. The sample mean is $2700 and the sample standard
deviation is $300.
a. What is the null a
STAT 8
Homework 1 Solutions
1. Below are the heights (rounded to nearest inch) of 20 male freshman college student athletes at
UCLA (University of California at Los Angeles) in 2010.
75, 66, 68, 70, 65, 67, 71, 71 , 72, 70, 73, 73, 71 , 73, 73, 71 , 70, 7
STAT 8
Midterm Practice Solutions
1. A shipping company analyzes their deliveries from the past year and creates the following
distribution table of the number of business days it took to deliver a package.
x
P(X=x)
1
0.70
2
0.10
3
0.05
4
0.05
5
a. What i
STAT 8
Midterm Solutions
Show all work. Write name and student ID on all pages.
Some useful formulas:
P(A and B)=P(A)+P(B)+P(A or B)
P(A and B)=P(A|B)P(B)=P(B|A)P(A)
P(A)=P(A and B)+P(A and B C )
P (A|B) =
P(A and B)
P (B)
.
If A and B are independent, th
Stats 8 spring 2014 (Baldi) FINAL version A
_- it
Name: - Student ID: -i g W K b
Keep your eyes on your own work. No electronic devices are allowed except for your graphing calculator.
Cheating will be reported to UCl and result in a grade penalty at the
Stats 8 spring 2017: Intro to Biostats
Dr. Brigitte Baldi, instructor
UCI class website at eee.uci.edu/17s/37730
(syllabus, exam dates, reading assignments, lecture notes, office hours)
All course-related questions must be posted on the EEE Message Board
Introduction to inference
PSLS chapters 14 and 15
Copyright Brigitte Baldi 2017
Reminder
Known properties of the sampling distribution of
If the population is N(,), the
sampling distribution is N(,n).
n
If not, the sampling distribution is
~N(,n) if n is
Homework 3: chapters 5 & 6
Chapter 5:
14. a) Response bias
b) nonparticipation bias
c) nonparticipation bias
72. If one question requires respondents to think about something that they may not have
otherwise considered, then the order in which questions a
Sampling distributions
PSLS chapter 13 (sections 13.1 through 13.4 only)
Part II of flipped lesson
Copyright Brigitte Baldi 2017
Population (all individuals)
Sample ( individuals)
statistic
parameter
(only 1 value)
(different values for
different random
Stats 8 winter 2017 (Baldi) Midterm 1
Name: _ Student ID: _
Keep your exam to yourself and your eyes on your work. No electronic devices are allowed at any time,
except for your calculator. Cheating will be reported and result in a grade penalty at the in
Correlation and Regression
PSLS chapters 3 and 4
Copyright Brigitte Baldi 2017
In a experiment, 16 student volunteers at
Subject
the Ohio State University drank a randomly
assigned number of cans of beer. Thirty
minutes later, a police officer measured
t
Collecting data
PSLS chapters 7 and 8
Copyright Brigitte Baldi 2017
Population versus sample
Sample
(data for some individuals)
Population
(data for all individuals)
statistic
parameter
population
sample
1
The role of randomness
How do you choose the ind
Probability
PSLS chapters 9 and 10
Copyright Brigitte Baldi 2017
Randomness and probability
Random event
Random variable
Probability of getting a given outcome for a random event
Properties of the event studied
Observed frequencies
Subjective / personal
Stats 8 winter 2017 (Baldi) Midterm 2 SOLUTIONS
Problem 1 (10 points) Overweight and obese women may avoid contraceptive methods they believe (often
incorrectly) to be associated with weight gain. Perhaps long acting reversible contraception (LARC) such a
Chi-square test for two-way
tables
PSLS chapter 22
Copyright Dr Brigitte Baldi 2017
Inadequate exposure to outdoor lighting conditions may increase the risk of
myopia in children. A study compared rates of myopia among randomly selected
young children (6
Descriptive statistics
PSLS chapters 1 & 2
Part II: issues and examples
Copyright Brigitte Baldi 2014
Quantitative or categorical variable? Ask:
What/who are the individuals/units in the data set?
What is being recorded about those individuals/units?
Is
One week of blood sugar measurements in mg/dl:
NNNNN
row-h-U'iul
HHINN
whwom
12
NNN
ran1H
43mm
ImilI-I
HUIO
l
O
(X)
p
NO NO
172-0 ,.
[30).-a1 Duo, M5) (yo, W6) Emma?) E0017 353 E50396)
gloock Surge-K (Mgldcx
206?
l
ago 2530
One variable data o
3. Fortwo eventsA and B, P(A) = .4, PH?) = .2 and PM (i B) = .08
a. Find P(AlB) PCA E) _ OK
as ,2
L\
b. FindP(B|A) : 7an 05/
mm _ 7T 2
c. AreAandB independent events? C(Alfb\ : ?(A\ :7 7% \Aclep.
Also, PCABVCEWL ?CAFIT>3 ;) ypAep
d. Are A and B mutually
STATS 8 Discussion 3 Slides Answer Key
Sampling Methods:
Ex 1 (Campus Bookstore)simple random sampling
Ex 2 (Google Intern)non-random sampling
Ex 3 (Political Polling)stratified sampling
Ex 4 (Health Services)multi-stage sampling
Study Biases:
Ex 1 (Campu