Examples of application of the 68-95-99.7 empirical rule
EXAMPLE 1
A software company finds that the average number of errors in its software per 1000 lines of code is 3
with standard deviation equal to 0.5. Use the 68-95-99.7 rule to answer the following
IT-223 - Assignment #1 Quintin Gray
Submit your assignment to the D2L Dropbox.
And again, please remember not to wait until the last minute in case you run into
glitches with D2L or your own computer.
All questions in this assignment should be saved into
Samir Shallwani
10/20/11
IT 223
Part 1
Trial
1
2
3
4
Total
Number of displayed
symbols
25
25
25
25
100
Number of correct
guesses
10
3
9
6
28
Percentage of
correct guesses
40%
9%
36%
24%
28%
Without any trials, there would be a 1/5, 20% chance of guessing
Samir Shallwani
Module 7
1) If the p-value =0.20, which is the best conclusion?
d)
Data do not provide enough evidence to reject H0
If p-value is LARGER than 0.05, the null hypothesis CANNOT BE REJECTED. The test
is not significant.
2) A study carried out
Module 3 project
a. What is the slope of this line? Express in simple language what the slope says about the
relationship of Damage to Distance?
Damage = 10.28 + 4.92 Distance
y= b0 +b1x b0 =intercept, b1 =slope
Slope of the regression line is an impor
DEPAUL UNIVERSITY
IT 403 Statistics and Data Analysis Homework#3 (Normal Distribution)
Instructions:
Answer all questions. However note that only question#s 1 and 4 will be graded. Though only
some questions will be graded, you MUST answer all questions.
Muhammed Durrani
IT-223
A6 Winter
Problem 1
Problem 2:
Muhammed Durrani
IT-223
A6 Winter
Problem 3:
Muhammed Durrani
IT-223
A6 Winter
Problem 4:
Muhammed Durrani
IT-223
A6 Winter
8.27 Getting angry at other drivers. Refer to Exercise 8.26. The same Pew Poll found that 38% of
the respondents shouted, cursed or made gestures to other drivers in the last year.
1.
(a) Construct a 95% confidence interval for the true proportion of U.S.
Question 1:
1) Using the Z-Table
The Z-Score is 1.48
1.48 = (x-470)/85
X = 595.8
2) Using the Z-Table
The Z Score is -0.25
-0.25 = (x-470)/85
X = 448.75
3) Z-Score for X = 580
1.29
Z-Score for X = 380
-1.06
Corresponding Areas
(1.29) = 90.15%
(-1.06) = 14
IT 223
A5
Probability
Problem 1#
Event= Machines being out of commission in each hour.
Number of outcomes= 0.03
P= 33%
Problem 2#
Sample Space= 0,1,2,3,4,5
Probability Model
0
1
2
3
4
5
1/50 1/50 1/50 1/50 1/50 1/50
0.02/5=0.04
40% chance that one of them
Muhammed Durrani
IT-223
Assignment 4
Problem 1:
B)
Regression Model:
Liquor Consumption= 21.965+0.722 Cirrhosis deaths
Wine Consumption = 20.335+2.862 Cirrhosis deaths
C) Wine and Cirrhosis death is the best predictor because in this scatterplot there are
Winter? What is winter to me? Winter to me is what I was tought growing up as a kid in Chicago. When
someone says "winter" the things that come to mind are snow, cold weather, snowman, christmas, present,
and santa! Also some negative things like traffic,
Jesse Jackson
IT-223 Assignment #7
Each question is worth 10 points.
Problem 1
The total study time for a statistics assignment in a population of college students was
approximately Normally distributed with a mean of 7.62 hours and standard deviation of
Assignment #5
Problem #1:
A popular test for a certain medical condition has about a 3.8% rate of false positive results. That
is, about 3.8% of people who do not have the disease will still have a positive test! A physicians
medical clinic administers th
IT-223 - Assignment #2
How to complete your assignment: All questions in this assignment should be saved into
a Microsoft Word document or any doc or RTF compatible file. PDF is also fine. This file
will then be submitted. When using SPSS, note that you c
Jesse Jackson
IT-223 Assignment #6
Problem #1 (10 points)
You ask your graduate student to roll a die 10,000 times and record the results. Give the expected
mean and standard deviation of the outcome. Part B: The die roll experiment is repeated (though
wi
Jesse Jackson
Coefficientsa
Model
1
Unstandardized
Standardized
Coefficients
Coefficients
B
(Constant
)
Std. Error
82.660
5.056
5.277
.427
Beta
t
.803
Sig.
16.350
.000
12.357
.000
a. Dependent Variable:
1) b0= 82.660 b1=5.277 r=.802 r2=.645
A) the Correla
Yamini Bangarusamy
ASSIGNMENT #4
1.
a.
b. The correlation coefficient is 0.803.
c. The scatterplot is linear, has a positive direction, and the strength of the scatterplot is
strong.
d. R2 = 0.645.
Change in x describes 64.5% of the change in y. 35.5% of
Question 1:
1) Using the Z-Table
The Z-Score is 1.48
1.48 = (x-470)/85
X = 595.8
2) Using the Z-Table
The Z Score is -0.25
-0.25 = (x-470)/85
X = 448.75
3) Z-Score for X = 580
1.29
Z-Score for X = 380
-1.06
Corresponding Areas
(1.29) = 90.15%
(-1.06) = 14
R^2-Coefficient of Determination. Square of correlation coefficient. R^2 tells you to what degree X
affects Y.
R = -1
R^2 = 1 or 100% Changes in X explain 100% of the variations in y. Y can be entirely predicted for a
given X.
R = 0.87
R^2= 0.76
Change in
10.17 Assessment value versus sales price. Real estate is typically reassessed annually for
property tax purposes. This assessed value, however, is not necessarily the same as the fair market
value of the property. Table 10.2 summarizes an SRS of 30 prope
9.17 DFW rates. One measure of student success for colleges and universities is the percent of
admitted students who graduate. Studies indicate that a key issue in retaining students is their
performance in so-called gateway courses.17 These are courses t
7.65 Sadness and spending. The misery is not miserly phenomenon refers to a persons spending
judgment going haywire when sad. In a recent study, 31 young adults were given $10 and randomly
assigned to either a sad or neutral group. The participants in the
IT 223
6.121
Blood phosphorus level in dialysis patients. Patients with chronic kidney failure may
be treated by dialysis, using a machine that removes toxic wastes from the blood, a function normally
performed by the kidneys. Kidney failure and dialysis
Data Analysis EDA Practice Problems
DO NOT SUBMIT
Answers to ALL odd numbered problems are in the text addendum
th
Problems are based on 8 edition numbering.
Students can find problems with similar wording or numbering in prior editions
1.127 Find proport
IT-223 Assignment # 7
1.
a.
Distribution of the Sample Means: N(7.62, 0.1170)
Mean is the same as the population Mean. The Standard Error is the
SD/SQRT(Sample Size)
Mean = 7.62
Standard Error = 1.85/SQRT(250)
b. Distance from Mean = 6.0-7.62 = -1.62
C
How to Succeed in IT223
DO
All the quizzes
All the assignments
Come to all the
classes
Engage, participate!
DO NOT
Fail to complete 12 /
20 quizzes
Fail to turn in 5 out of
7 assignments
Come to half the
classes
Nap
1
My Office Hours
Mondays Wednesdays
Module #1
Center of a distribution
Spread of a distribution
Quartiles
5-Number Summary and Boxplot
Outliers
Learning Objectives
By the end of this lecture, you should be able to:
Recognize how scales, mislabeled axes, etc on charts can be misleading
Des
Module 1: Exploratory data analysis
Introduction
Statistics is the science of collecting, analyzing, displaying and
interpreting data. The first question we should ask is: Why
learn statistics?
The NY Times published an article in 2009 titled For Todays
G
Jesse Jackson
IT-223 - Assignment #3
All questions in this assignment should be saved into a Microsoft Word document or any
doc or RTF compatible file.
Question #1 (20): Use the dataset callcenter80.sav for this question, it can be found
on the class chec
IT-223 - Assignment #4
Create a Word document in which you paste all graphs and provide your discussion. For
credit, your discussions of the questions asked below MUST demonstrate that you have
thought about and can therefore describe the underlying conce
IT-223 - Assignment #1
Submit your assignment to the D2L Dropbox.
And again, please remember not to wait until the last minute in case you run into
glitches with D2L or your own computer.
All questions in this assignment should be saved into a Microsoft W
IT-223 Assignment #6
Problem #1 (10 points)
You ask your graduate student to roll a die 10,000 times and record the results.
(a) Give the probability model, expected mean and standard deviation of the outcome.
(b) The die roll experiment is repeated (thou
IT-223 - Assignment #3
All questions in this assignment should be saved into a Microsoft Word document or any
doc or RTF compatible file.
Question #1 (15): Use the 68-95-99.7 rule to answer the all but the last problem in this
question. The ACT standardiz