STAT 511 - 5 & 6 Homework SOLUTION 11
Ten points for each question, a total of 60 points.
1. The following data refers to yield of tomatoes (kg/plot) for four different levels of salinity. Use the F
test at level =0.05 to test for any differences in true
Examples for chapter 3
A store carries flash drives with either 1 GB, 2 GB, 4 GB, 8 GB, or 16
GB of memory. The accompanying table gives the distribution of Y =
the amount of memory in a purchased drive:
Let X = the number of days of sick leave taken by
Chapter 8
A statistical hypothesis, or just hypothesis, is a claim or assertion
about population characteristic
Definition
The null hypothesis, denoted by H0, is the claim that is initially
assumed to be true (the prior belief claim). The alternative
h
Practice Exam 2
1. The breaking strength of a rivet has a mean value of 10,000 psi and a standard deviation of 500 psi.
(a) What is the probability that the sample mean breaking strength for a random sample of 40 rivets is
between 9950 and 10,250?
(b) If
Statistics 511-8&10
Midterm Examination 2
Tuesday, November 12th, 2015
Name (please print) :_
Section: _
Time: 60 minutes
Please sign below to indicate your agreement with the following honor code.
Honor code: I promise not to cheat on this exam. I will n
Chapter 7
Suppose that the parameter of interest is a population mean and that
1. The population distribution is normal;
2. The value of the population standard deviation is known.
We have
and
This provides a random interval that contains the populati
Chapter 9
The Two-Sample t Test and Confidence Interval
Theorem
When the population distribution are both normal, the standardized
variable
(9.2)
has approximately a t distribution with df v estimated
from the data by
The Two-Sample t Test and Confide
1. The following data specify scores of an exam for students in a class.
75
89
81
85
89
81
95
98
80
81
84
84
93
71
81
68
64
74
80
90
67
82
70
82
72
85
69
69
70
63
66
72
66
72
60
87
85
81
83
88
A frequency table is provided below.
Class
60 under 65
65 unde
Chapter 10
Example 1 Consider an experiment in which several different types of
shipping boxes were compared with respect to compression strength
(lb).
Notations
i = 1, I is a group index
xi, j = the jth measurement taken from the ith population,
sam
1. The number of space shuttle flights taken by each of 313 astronauts are
summarized in the following frequency distribution.
Flight
0
1
2
3
4
5
6
7
Frequency(# astronauts)
67
71
57
40
39
30
6
3
Relative frequency
0.2140575
0.226837061
0.182108626
0.1277
Chapter 6
Example 15 Suppose we want to find the flaw ratio p of new bike
helmets manufactured by a certain company. How can we estimate
the probability of flawed helmet?
A statistic is any quantity whose value can be calculated from sample
data (e.g. s
Example for Chapter 2
Example 8 (2.2.1). Two bags, bag #1 contains two balls marked 1 and
2 respectively; bag #2 contains three balls marked 1, 2, and 3
respectively. Pick a ball from bag #1, and then pick another ball from
bag #2, how many different pos
STAT 511-1
QUIZ 2
KEY
A psychiatrist believes that 60% of all people who visit doctors have problems of a psychosomatic
nature. He decides to select 9 patients at random to test his theory. Assume the psychiatrists theory
is true.
1. What is the probabili
STAT 511-1
QUIZ 1
KEY
A data set of 24 entries are listed below.
0.2
2.1
4.4
0.2
2.7
5.6
0.3
3.1
6.1
0.4
3.3
6.6
1.3
3.5
6.7
1.6
3.7
7.4
1.6
3.9
8.0
2.0
4.1
8.3
1. Construct a stem-and-leaf display of the data.
2. Find out the median and the rst and the t
a. AlUAZUA3
b. AlﬂAzﬂ/h
c. AlnAz’nAs'
d. (A1 (WA; mA§)u(A{mA2 nA§)u(A,’mA£ HA3)
e. A1U(A2FWA3)
a. P(A UB) = .50 + .40 — .25 = .65.
b. P(neitherA nor B) = P(A’ n B’) = P(A u B)’) = 1 — P(ALJB) = 1 — .65 = .35.
c. The event of
Examples for Chapter
4
Example 4 Let X be the angle measured clockwise from a reference
radius line on a circle. One possible pdf for X is
Example 5 Time headway in traffic flow is the elapsed time
between the time that one car finishes passing a fixed
Example for chapter 5
Example 25 The time that it takes a randomly selected rat of a certain
subspecies to find its way through a maze is a normally distributed rv
with = 1.5 min and = .35 min. Suppose five rats are selected.
Let X1, . . . , X5 denote t
STAT 511 - 5 & 6 Homework SOLUTION 9
Ten points for each question, a total of 60 points.
2+2+2+2+2
1. A new design for the braking system on a certain type of car has been proposed. For the current
system, the true average braking distance at 40 mph under
Name:
ANSWER
.
(6)
Statistics 511-6, Quiz 4
(4)
1. A random sample of 10 houses in Big Rapids, each of which is heated with natural
gas, is selected and the amount of gas (therms) used during the month of January is
determined for each house. The resultin
Name:
ANSWER
.
(5)
Statistics 511, Quiz 3
The heights of men in a certain population follow a normal distribution with mean 69.7
inches and standard deviation 2.8 inches.
a) If a man is chosen at random from the population, find the probability that he wi
1. Short-answer questions.
(a) The number of contaminating particles on a silicon wafer prior to a certain rinsing
process was determined for each wafer in a sample of size 100, resulting in the
following frequencies:
Number of particles 0
Frequency
1
1
2
Name:
ANSWER
.
Statistics 511-8&10, Quiz 1
n
s
n
2
yi y
i
1
n 1
y
2
i
ny 2
i
1
n 1
Consider the following observations on shear strength of a joint bonded in a particular manner:
20.0
4.4
33.1
66.7
81.5
22.2
40.4
16.4
73.7
36.6
109.9
a. Determine the v
Name:
ANSWER
.
(4) (3)
Statistics 511-8&10, Quiz 2
An electronics store has received a shipment of 20 table radios with connections for external
devices. Twelve of them have two connection slots, and the other eight have a single slot.
Suppose that six of
Hw3 solution
b. P(A U B)=0.6+0.4-0.3=0.7
c. P(neither A nor B) =P(A B)=1-0.7=0.3
d. The event of interest is A B: from a Venn diagram, we see P(AB)=P(A)-P(AB)=0.6-0.3=0.3
e. From a Venn diagram, we see that the probability of interest is P(exactly one)=P(
Statistics 511 Midterm Exam Fall 2016
Name:
Purdue ID: > 0
Write your answer and all the relevant derivations on the
exam paper (1) (6): There are 2 events A1, A2. P(A2) = 0.65, P(A1UA2) = 0.86.
P(A1 0 A2) = 0.2. Compute the following probabilities: (A Ve
If you find a mistake, please email me ASAP: [email protected]
1. N( = 75, = 13.7)
a. 85%ile Z = 1.04, So X = 75 + 13.7(1.04) = answer: 89.248
b. Z2 = (90 75)/13.7 = 1.09 0.8621
Z1 = (80 75)/13.7 = 0.36 0.6406
Take 0.8621 0.6406 = answer: 0.2215
c.
1. Suppose birth weights of human babies are normally distributed with a mean of 120
ounces and a stdev of 16 ounces (1lb = 16 ounces).
a. What is the probability that a baby is at least 9 lbs 11 ounces?
Z = (155 120)/16 = 2.19, the probability is 0.0143.
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