Stat 2 Fall 2014
HW #3
1. For each of the following three sets of numbers, find the median, then find the average
(show your work):
a. 8 9 10 11 12
b. 8 9 10 11 100
c. 8 9 10 11 1000
Describe what you have discovered regarding averages and medians regardi
Stat 2 Fall 2014
Homework 10
1. Sixteen hundred draws will be taken from the following box
True or false and explain:
a) The expected value for the percentage of 1s from the box is exactly 75%.
b) The expected value for the percentage of 1 for the percent
Fall 2014 Stat 2
Homework #2
1. In searching for examples of histograms on the internet, I came across this page, which
had the data given in the following table.
From: http:/cribbd.com/learn/maths/data-handling/construct-and-interpret-a-histogram
Distanc
`
Fall 2014
Stat 2
Homework 11
Much of this first problem does not require any reading from the book. It requires you to think
critically about what is going on in the actual problem critical thinking.
1. Pew Research conducted a random telephone (includi
SOLUTIONS
Fall 2014 Stat 2
Homework 13
1. Suppose two psychologists each perform the same experiment. Each experiment involves 400
randomly selected rats from the same population. Both experiments have the same null
hypothesis, that the percentage of rats
SOLUTIONS
Fall 2014 Stat 2
Homework 12
Interpretation of confidence intervals redux:
1. Based on responses of 1467 subjects in a General Social Survey, a 95% confidence interval for
the average number of close friends was calculated to be (6.8, 8.0). Stat
Solutions
Stat 2 Fall 2014
Homework 9
1. Election Day is coming up. Suppose that there are only two candidates in this race, Tweedle-Dum
and Tweedle-Dee, and that Tweedle-Dum receives almost 50% of the total vote. An exit poll of
voters is taken to try to
SOLUTIONS
Stat 2 Fall 2014
Homework 10
1. Sixteen hundred draws will be taken from the following box
20,000 0s
60,000 1s
True or false and explain:
a) The expected value for the percentage of 1s from the box is exactly 75%.
True the EV for percentage is e
Fall 2014 Stat 2
Homework 7
SOLUTIONS
1. A 6-sided die is rolled six times. Two possible sequences of results are:
i)
4 4 4 4 4 4
ii) 4 3 4 2 4 1
(The die must land in the order given first roll 4, second roll 3 in ii) for example)
Which of the following
Stat 2 Fall 2014
Homework 8
Solutions
1. Election Day is coming up. Suppose that there are only two candidates in this race, Tweedle-Dum
and Tweedle-Dee, and that Tweedle-Dum receives almost 50% of the total vote. An exit poll of
voters is taken to try to
Stat 2 Fall 2014
Homework #6
1. A class had two midterms. The average for midterm 1 was 70 with an SD of 10. The average for
midterm 2 was 75 with and SD of 7. The correlation between the two was about 0.5. The scatter
diagram was football shaped.
a. What
Stat 2 Fall 2014 HW #4
You will have to use Table A for many of these problems.
1, The Law School Admission Test has scores ranging from 120 to 180, with an average ofabout
150, The SD is approximately 10. You may assume that the test scores are well appr
Stat 2 Fall 2014
Homework 9
1. Election Day is coming up. Suppose that there are only two candidates in this race,
Tweedle-Dum and Tweedle-Dee, and that Tweedle-Dum receives almost 50% of the
total vote. An exit poll of voters is taken to try to predict t
Stat 2 Fall 2014
Homework #6
1. A class had two midterms. The average for midterm 1 was 70 with an SD of 10. The
average for midterm 2 was 75 with and SD of 7. The correlation between the two was
about 0.5. The scatter diagram was football shaped.
a. What
- - ~. m 1 cc
Statistics 2 I? F F1
Second Midterm Exam SIM V f] cue e .-
Spring 2002 _.ru-1,Ihe_-rg-,W.1
Show your work. A correct ensure-r with me justication or r'rrccnrrecl.i
reasoning wm receive no credit. Use the normal table at the end of this
exam
Stat 2
Administrative stuff
lecture 2
Things you need to know
Lecture notes will be posted after
class on bcourses (NOT bspace)!
Access bcourses:
https:\bcourses.berkeley.edu
Corrections from last time
My office is 449 Evans
Grading scheme is as I a
STAT 2 Lec Sec 1: Fall 2014
(Course Control Number: 87303)
INSTRUCTOR: Ann Kalinowski
Email address ann.kalinowski@berkeley.edu
Office: 449 Evans Hall
OFFICE HOURS: TTh 11- noon, 1:30pm-3pm
I will usually be in my office all day, except for 1 hr lunch, un
Announcements
Quiz next Wednesday covering from Chapter 16
through Chapter 18
DSP students please let GSI Taly know when you
are going to take the quiz.
In the syllabus I said I would skip chapter 19 on
surveys. I will not cover it in depth, but I will ma
Announcements
Midterm 1 is finished grading. You should have
gotten an invitation to view your graded
midterm on Gradescope.
You will have until 11:59pm Friday to ask for a
regrade. If you do not ask for a regrade by then,
your grade on the midterm will s
Chapter 10 - Regression
So far weve looked at correlation as a measure
of the linear relationship between two
variables. The closer the correlation is to + or
1, the more tightly the points cluster around
the SD line, and the stronger the relationship.
I
Stat 2 Fall 2014
Homework 10
1. Sixteen hundred draws will be taken from the following box
True or false and explain:
a) The expected value for the percentage of 1s from the box is exactly 75%.
b) The expected value for the percentage of 1 for the percent
Stat 2 Fall 2014
Homework 8
1. Election Day is coming up. Suppose that there are only two candidates in this race,
Tweedle-Dum and Tweedle-Dee, and that Tweedle-Dum receives almost 50% of the
total vote. An exit poll of voters is taken to try to predict t
Stat 2 Fall 2014
Homework 1
1. A researcher examined published studies about a new treatment for patients with heart
attacks. He found that if the study randomized patients between control and treatment
groups, about 9% of patients in the treatment group
Fall 2014 Stat 2
SOLUTIONS
Homework #2
1. In searching for examples of histograms on the internet, I came across this page, which had the
data given in the following table.
From: http:/cribbd.com/learn/maths/data-handling/construct-and-interpret-a-histogr
`
Fall 2014 Stat 2
Homework 11
Much of this first problem does not require any reading from the book. It requires you to think critically
about what is going on in the actual problem critical thinking.
1. Pew Research conducted a random telephone (includi
Fall 2014 Stat 2
SOLUTIONS - revised
Homework 5
1. (Apologies in advance this problem has a lot of parts and tedious calculations. But you should
see how all the parts go together for a correlation and regression line by the end.) A teaching
assistant for
Spring 2015 Stat 2
Homework 11
1. A marketing study conducts 60 significance tests about means and percentages for several
groups. Of them, 3 tests show statistical significance (p-values less than 5%). The final report for
the study stresses only the tes
Stat 2 Spring 2015
HW #3
1. Consider the following dataset:
X
10
20
30
40
50
Y
10
30
50
30
10
a) Make a scatterplot of Y vs X (2 pts.)
b) Describe the relationship between X and Y (Is it weak or strong? Is it linear?) (1 pt.)
c)
Find the correlation betwe
Stat 2 Spring 2015
1.
HW 7
A weather forecaster states, The chance of rain is 50% on Saturday and 50% again on Sunday.
Theres a 100% chance of rain sometime over the weekend. True or false and explain your
answer. (1 pt.)
2. Based on past experience, Rome
Spring 2015 Stat 2
1.
Homework 8
400 draws are made at random from the box
10,000
0
30,000
1
True or false and explain: (1 pt. .5 for correct t/f, .5 for correct reason)
a. The expected value for the percentage of 1s among the draws is exactly 75%.
b. The
Stat 2 sect. 2 Spring 2015
HW #4 due Wednesday Feb. 25
1. In the beginning of a semester, a statistics class had two quizzes, both scored on the basis of 50
points. The average of quiz 1 was 30 with an SD of 6; the average of quiz 2 was 25 with and SD
of