SECTION 2: Exercises
2.9 Using the Pivot excel file from class (on blackboard), answer the following two questions by
creating the appropriate pivot tables. Is the average age of renters younger than
SECTION 5: Exercises
5.1* Find the area under the standard normal curve.
a. between z = 0 and z = 1.90 P(0<z<1.9) = 0.4713
b. between z = 0 and z = -1.75 P(-1.75<z<0) = P(0<z<1.75) = 0.4599
c. between
Econ 18 Midterm Prep
Question 1
Question 2
Question 3
Question 4
Question 5 Part I
Q5 Part II
The following data are taken from a study investigating the use of a technique called radionuclide
ventric
Problem Set 11
Statistics - NYU, Fall 2015
Ercan Karadas
[1] Suppose annual returns on two stocks, R1 and R2 , are normally distributed with
the following distributions:
R1 N (0.1, 0.22 )
and
R2 N (0.
Problem Set 12
Statistics - NYU, Fall 2015
Ercan Karadas
[1] Based on a sample of 25 observations, the regression model
yi = b0 + b1 x1 + ei
was estimated. The least squares estimates obtained were as
Problem Set 12 - Solutions
Statistics - NYU, Fall 2015
Ercan Karadas
[1]
a)
SSR
SST SSE
268 204
=
=
= 0.2388
SST
SST
268
23.88% of the variation in the dependent variable can be explained by the
varia
Problem Set 4 - Solutions
Statistics - NYU, Fall 2015
Ercan Karadas
[1]
a) Since each outcome is equally likely this probability is simply equals to
# of outcomes in E
2
=
# of outcomes in S
10
Altern
Problem Set 10 - Solutions
Statistics - NYU, Fall 2015
Ercan Karadas
[1]
a) The sample data
n = 44,
X = 126,
s2 = 15
and since the true population variance is unknown we use tdistribution to
construct
Problem Set 10
Statistics - NYU, Fall 2015
Ercan Karadas
[1] Hoping to lure more shoppers downtown, a city builds a new public parking garage
in the central business district. The city plans to pay fo
Problem Set 9 - Solutions
Statistics - NYU, Fall 2015
Ercan Karadas
[1] Random variable: X: Weight of a cereal box, and we know that X N (20, (0.6)2 ).
2
2
2
a) X = = (0.6) the standard error of the s
Problem Set 9
Statistics - NYU, Fall 2015
Ercan Karadas
[1] A company produces breakfast cereal. The true mean weight of the contents of its
cereal boxes is 20 ounces, and the standard deviation is 0.
Problem Set 8
Statistics - NYU, Fall 2015
Ercan Karadas
[1] A company services home air conditioners. It is known that times for service calls
follow a normal distribution with a mean of 60 minutes an
Problem Set 2 - SOLUTIONS
Statistics - NYU, Fall 2015
(Econ UA - 18.06)
[1]
a) Denote Education and Family Income variables with e and f , respectively.
Then sample means are:
10
i=1 ei
18 + 14 + . .
Problem Set 1
Solutions
Stat UA-18.02
1.
(a)
(b)
2. For this exercise download the data le Price-Quantity from the Data folder on
NYU-Classes.
(a)
(b)
(c)
(d) Yes, indeed there is a negative relations
Econ 18 Midterm Prep Solutions
Question 1
Question 2
Question 3
Question 4
Question 5
The following data are taken from a study investigating the use of a technique called radionuclide
ventriculograph
Statistics Lecture 10/5/15
Chapter 8 Regression Wisdom
8.1 Examining Residuals
-difficult to tell without residuals whether graph is straight enough or not
Residual scatterplot might show bends, diffe
Statistics Lecture 10/13/15
Ladder of Powers
-use to re-express a scatterplot to make it straighter
-x variable does not change, only y variable is re-expressed
-leave in Power 1 if data is less likel
Statistics Lecture 9/28/15
Midterm Chapter 1-7, no excel or statcrunch or large data questions
-basic formulas, definitions, concepts
3 different formulas to calculate r (correlation coefficient)
- r
Statistics Lecture 9/30/15
Correlation and Prediction
Ex: can predict using related variables (not GPA and height)
-discount information contained in x when using regression line
-regression to the me
Statistics Lecture 9/16/15
3 Important things when analyzing graph
Shape: using mode, symmetry, outliers, unimodal features
Center: median, mean
Spread: range= max- min, IQR = Q3 Q1 , variance, standa
Statistics Lecture 9/23/15
-can estimate area under curve with 68-95-99.7 rule
-or use z-scores
-top quartile a little more than (smaller value) z=1 (100% - 68% <- n/2 = 16%)
-or find approximately 0.
Statistics Lecture 9/14/14
Chapter 3: Displaying and Summarizing Quantitative Data
Histogram: chart that displays quantitative data
-helpful to show distribution of data
-divides quantitative variable
Statistics
Chapter 1
Data: any collection of numbers, characters, images, at other items that provide info
about something
Think about: what questions to answer, what data means
Statistics: particular
Statistics Lecture 9/9/15
Review from last week:
Ordinal variable: reports order without natural units
-when deciding between if a variable is categorical or quantitative, need to
consider how data wi
Statistics and Decision Analysis
Fall 2012
Solutions to Assignment 1
1)
U. Bus
Not U. Bus
MBA
0.08
0.21
0.29
Not MBA
0.16
0.55
0.71
0.24
0.76
1
From the above table, we get:
a) P(MBA/ U. Bus) = P(MBA
Problem Set 8 - Solutions
Statistics - NYU, Fall 2015
Ercan Karadas
[1] Let X denote the time for service calls, then X N (60, 102 ).
6560
10 )
P ( 5060
10
a) P (X > 65) = P (Z >
= P (Z > .5) = 1 F (.
Problem Set 7 - Solutions
Statistics - NYU, Fall 2015
Ercan Karadas
[1]
a) To show that f (x) is a probability density function, we need to show that:
i. f (x) 0 for all x
2
ii.
f (x)dx = 1
0
From the
Problem Set 6 - Solutions
Statistics - NYU, Fall 2015
Ercan Karadas
[1]
a) p1 + p2 + p3 1
b) p1 + p2 + p3 = 1
c) p1 + p2 + p3 = 12/10 > 1, therefore they cannot be mutually exclusive. They
might be co