QBA 2302 Assignment 2
Describing Data Using Numerical Summaries
1. In June an investor purchased 300 shares of Oracle (an information technology
company) stock at $20 per share. In August she purchased an additional 400 shares
at $25 per share. In Novembe

Review for Exam 2
1. In a statistics class with 15 males and 13 females, 5 students are selected to put problems on the board. a. What is the probability that of the 5 selected 3 are females?
b. What is the probability that of the 5 selected 2 are m

CHAPTER 6: INFERENCES ABOUT TWO
POPULATION CENTRAL VALUES
6.1 DEPENDENT AND INDEPENDENT SAMPLES In chapter 5, we studied methods for testing a claim about the value of a population parameter. In this chapter, we will learn how to test a claim compari

Trey Cambere
QBA TR 3:30-4:45
1-14-16
How I May Apply Statistics in My Future Work
Statistics is a part of everyday culture whether you realize it or not, you always are
weighing some sort of probability or recognizing the likelihood of something to occur

Answers, Class Example #1
MegaStat Data Summaries for Class Example 1
(a)
Frequency Distribution - Qualitative
SATISFACTION
frequency
17
20
13
50
L
M
H
percent
34.0
40.0
26.0
100.0
(b)
Frequency Distribution - Qualitative
TRAINING
frequency
percent
N
21
4

QBA 2302 - Example 16 — Correlation and Regression Analysis
The following data is from a chain of 50 convenience stores. Each row or record of data
contains the following variables:
(1) Annual sales (in thousands of dollars)
(2) Average weekly auto trafﬁc

QBA 2302 Example #4 Introduction to Probability
Assume you are inspecting the wrapping of candy bars coming off a
production line. The quality of the wrapping of an individual bar
either passes inspection or fails the inspection. From previous
inspections

QBA 2302 Example 14 Correlation and Simple Linear Regression Analysis
A business is interested in relating the amount of sales (in $1,000s) of its salespersons to
the number of years of employment. Data was collected on 10 salespersons.
Years of
employmen

QBA 2302 Example #5 Binomial Probability Distribution
An electrical products distributor buys a 1,000 power strips from a
supplier. When each shipment of 1,000 power strips arrives, the
distributor takes a random sample of 15 power strips from the shipmen

QBA 2302 - Example 8 Estimation and Confidence Intervals
I. From past records it is known that the average (mean) life of a battery used in a
digital clock is 305 days. The battery was recently modified to hopefully last longer.
A sample of 36 of the modi

QBA 2302 Example #9
Estimation and Confidence Interval for a Population Proportion
The policy of the Suburban Transit Authority is to add a bus route if more than 55
percent of the potential commuters indicate they would use the particular route. A
sample

QBA 2302 - Example 6 - Normal Probability Distribution
Assume that the random variable, Z, has a normal distribution with a mean of zero and a
standard deviation of one. (This distribution is known as the standard normal
distribution.)
In a study involvin

Answers, Class Example 11
Part 1
1. H0: = 0.10
H1: > 0.10
2. Test Statistic = Z =
11
0.10
75
1.35
0 (1 0 )
0.10(1 0.10)
75
n
p 0
3. P-value = 0.0890
4. Fail to reject H0 since the p-value > 0.05
5. The sample proportion, p
11
0.1467, would not be consi

Answers, Class Example #10
1.
(a)
Give the null and alternative hypotheses for this situation.
H0: = 305 (Modification represents no improvement)
H1: > 305 (Modification represents an improvement)
(b)
Z
Value of the Test Statistic: Z = -2.00
X 0 311 305
3

Answers, Class Example #4
5
0.05 or 5%
100
1.
Pr(the wrapping on a single bar is defective) =
2.
Pr(the wrapping on a single bar is not defective) = 1
3.
Pr(2 bars both have defective wrapping) = 0.05 0.05 0.0025 or .25%
4.
Pr(Either of 2 bars or both ar

QBA Chapter 1
01/14/2016
What is statistics: Is a major branch of mathematics that may be defined as follows
Statistics is the science of collecting data, organizing or describing
it, and ultimately drawing conclusion from it to aid in decision
making.
S

=[_1,_3,_7,_9 ]
=[_2,_3,_8,_9
[,
]
Part A: =[_3,_9 ]
Part B: [,
=[_1,_2,_3,_7,_8,_9 ]
Part C: No, the union does does not contain all of the elements of the sample spac
ments of the sample space.
=[_3,_5,_6,_10
[,
]
=[_3,_4,_6,_9
[,
]
Part A:
=[_3,_6
[

5.6 c
d
0.25
0.25
5.8 a
b
0.2
0.4 < P(X < 400) < 0.6
5.14
$24 million
$ 1 million
5.16
$54,000
$14,400
5.18 a
b
c
d
0.524
-0.674
0.842
-0.253
5.20 a
b
c
d
e
0.9772
0.3674
0.0062
92.8
between 70 and 90
5.24 a
0.2266
b
0.2266
c
0.5468
d [i] symmetric
[ii] a

[a] Categorical, nominal (The response is categorical because the responses can be grouped
into classes or categories, in this case yes/no. The measurement levels are nominal
because the responses are words that describe the categories.)
[b] Categorical,

QBA2302Example1DescribingDataUsingTablesandCharts
The following data is from a chain of 50 convenience stores. Each row or record of data contains
the following variables:
(1)
(2)
(3)
(4)
(5)
(6)
(7)
1
2
3
4
Annual sales (in thousands of dollars)
Average

Answers, Class Example #16
1.
SALES
2.
COMP; it has the highest correlation with SALES
3.
Since the sample correlation coefficient between SALES and COMP (-0.850) is in absolute
value > the 5% critical value of 0.279, we would conclude that SALES and COMP

Answers, Class Example #9
The policy of the Suburban Transit Authority is to add a bus route if more than 55
percent of the potential commuters indicate they would use the particular route. A
sample of 70 commuters revealed that 49 would use a new propose

Answers, Class Example 15
(a) 125 homes
(b) SQFT, AGE, BEDRMS
(c) SQFT; it has highest correlation with PRICE
(d) Y = 85.113X 64,555
(e) Yes; the p-value = 2.56E-34
(f) For each additional square foot of the size of the home, the price is estimated to inc

QBA 2302 - Example 3 Displaying and Exploring Data
Using the Example 3 data , create the data summaries described below.
(a)
Produce the following descriptive statistics for the annual sales of the 50 stores
SALES by using the MegaStat command, Descripti

QBA 2302 Example 2
Describing Data Using Numerical Summaries
Using the Example 2 data, create the data summaries described below.
(a)
Produce the following descriptive statistics for the annual sales of the 50 stores
SALES by using the MegaStat command,

Chapter 8 QBA
Reasons to sample:
1. to contact the whole population would be time consuming
2. cost of studying all the items in a population
3. the physical impossibility of checking all items in the population
4. the destructive nature of some tests
5.