B Bus 215 B
Answer Correction
#1 The variance is computed as the average squared deviation of each number from
its mean. The variance is closer to standard deviation, but stand deviation is not
squared, and variance is squared, therefore the standard devi
For most applicationsThe units for the variance are always squared this is why the standard devia
The median selling price of new homes in a state in 2002 was $112,800, $40,000 is the most plausible
0.55
0.57
0.57
0.68
0.71
0.78
0.86
0.89
0.91
0.97
1.14
1
. ln-Class Regression Problem
m-_-
l-lmm-
-_-
11-m
. mn-
-_-
_M-
- 3. Find the average for x and the average for y
N- 1+5 A 31? ,
/\" '37.? 2. q 3~ T Li's (a
)
b. Find pearson correlation coefficient ( r)
m
67.37
218. 00
n 2x3- ixi ('awm
Grizelda Samano
Nov 16, 2016
Stats 212 Lab 13
INTRODUCTION
In order to identify if it is cheaper to buy groceries at a Safeway store vs. a
Wal-Mart store, a comparison of two population means using dependent samples
(paired t-test) was used. The paired t-
ConceptsforExam2
*Thislistismeanttohelpguideyourstudying.ItmayNOTbeanexhaustivelist.*
NormalDistribution(more in context with distribution of sample mean and sample proportion)
Beabletocalculateprobabilitiesforanormalrandomvariableusingthenormaltable
Be
Selects 140 dealerships randomly, surveys all customers- cluster
Stratified- number of individuals sampled from each stratum should be proportional to the size of the
strata in the population. Grouped, then obtain random sample from each group. 10 compani
Biology 251
6 October 2009
Exam Two
FORM W
PRINT YOUR NAME AND ID NUMBER in the space that is provided on the answer sheet, and then blacken
the letter boxes below the corresponding letters of your name and ID number. You will have 4 points
deducted if yo
Question 1: (Dont Worry about this question)
It is desired to test the claim that a steady diet of wolfbane will cause a
lycanthrope (werewolf) to lose 10 lbs. over 5 months. A random sample of 49
lycanthropes was taken yielding an average weight loss ove
Statistics Project
I investigated the proportion of plants kept outside of tenants apartments and the
proportion of plants kept inside tenants apartments in the Chinook Apartment complex. My
null hypothesis was that H0: p1 = p2, both proportions are equal
Lab 10 Spring 2016
Exam 2 Review
1. Assume that z scores are normally distributed with a mean of 0 and a standard
deviation of 1. If P(O < z <a)= 0.3577, find a.
2. Assume that z scores are normally distributed with a mean of 0 and a standard
deviation of
STAT212
Practice Questions for Exam 2
1. An investigator claims that = the average weight of passengers flying on small planes exceeds the FAA guideline of
average total weight of 185 pounds (passenger weight including shoes, clothes, and carry-on). Suppo
STAT212
Exam 2 Summer 2015
Name_
Multiple-Choice Part: Each multiple-choice question is worth 2 points.
1. Which of the following would be an appropriate alternative (research) hypothesis?
A) The mean of a population is less than 55.
B) The mean of a sam
ConceptsforExam2
*This list is meant to help guide your studying. It may NOT be an exhaustive list.*
Normal Distribution (more in context with distribution of sample mean and sample proportion)
Be able to calculate probabilities for a normal random varia
Class examples Probability of events, and additive rules (Sect. 2.4-2.5)
1. The probabilities that a car mechanic will service 3, 4, 5, 6, 7, or 8 or more cars on any given workday are 0.12,
0.19, 0.28, 0.24, 0.10 and 0.07, respectively. What is the proba
WASHINGTON STATE
g: UNIVERSITY
/ VANCOUVER
Probability and Statistics
STAT 360, Fall 2016
Class examples Introduction to Statistics and Data Analysis
1. The following is data associated with a study conducted at Virginia Polytechnic Institute and State
Class examples (Sect. 3.3)
1. Let T represent the time until failure (in years) of a randomly selected component. We believe that T has density
function f (t) = 0.5 e0.5t, t 0.
(a) Verify that f (t) is indeed a density function.
(b) What is the cumulative
Class examples Conditional probability, independence, and the product rule (Sect. 2.6)
1. In a city, 60% of all households get Internet, 80% get cable, and 50% get both services. If a household gets at
least one of these services:
(a) what is the probabil
Class examples Counting sample points (Sect. 2.3)
1. An employee from Washington state can choose among three group life insurance plans and five group health
insurance plans. If the employee chooses one life insurance plan and one health insurance plan,
Binomial and Multinomial Distributions
October 20, 2016
Bernoulli Trials
An experiment with only two possible outcomes, typically denoted success and failure.
If P (success)=p, then the P (f ailure) is 1 p (sometimes denoted q).
Note that success does not
Class examples (Sect. 3.1-3.2)
1. Specify if the random variables representing the following are discrete or continuous:
(a) The lifetime of a device:
(b) Number of students in a random class:
(c) Number of trains arriving to a station:
(d) Time until the
Class examples (Sect. 4.1)
1. The number of interviews that a student has prior to getting a job is represented by the random variable X with
36
probability function () = 49 2, for x = 1,2,3. Find the expected number of interviews prior to getting a job.
Normal Probabilities
Common Data
Mean
Standard Deviation
7
6
Probability for X <=
X Value
Z Value
P(X<=7)
7
0
0.5000
Probability for X >
X Value
Z Value
P(X>9)
9
0.33333333
0.3694
Probability for X<7 or X >9
P(X<7 or X >9)
0.8694
Probability for a Range
F
Paired t Test
Data
Hypothesized Mean Diff.
Level of Significance
0
0.05
Intermediate Calculations
Sample Size
DBar
degrees of freedom
SD
Standard Error
t Test Statistic
Two-Tailed Test
Lower Critical Value
Upper Critical Value
p-Value
Reject the null hypo
"Dow Dogs" Population
Parameters
1Yr-Return
Mean
7.6570
Variance
84.8352
Standard Deviation
9.2106
"Dow Dogs" Population
Parameters
1Yr-Return
Mean
7.6570
Variance
84.8352
Standard Deviation
9.2106
Stock
AT&T
Verizon
Merck
Pfizer
GE
DuPont
Johnson & Johns
For the Mean Sales Invoice Amount
Data
Population Standard Deviation
Sampling Error
Confidence Level
Intemediate Calculations
Z Value
Calculated Sample Size
25
5
95%
-1.9600
96.0365
Result
Sample Size Needed
97
For the Mean Sales Invoice Amount
Data
Popul