31 Jan I need someone who has experience in statistics to help me with this Test after 1 hour. I have uploaded the study materials and test sample. The payment is here and I will send questions on Whats
I need someone who has experience in statistics to help me with this Test after 1 hour.
I have uploaded the study materials and test sample.
The payment is here and I will send questions on Whatsapp.
Instructions of Test-2 (STAT-101)
The due date of Test 2 is Monday, January 30, 2023, at 11:00 PM.
Test 2 covers the material of Weeks 5, 7 & 8
The test consists of 25 questions
10T/F (0.25 marks each) and 15MCQ (0.5marks each)
Total Marks = 10
You have only one attempt.
You have a time limit of 5 hours (300 minutes).
This assignment will be saved and submitted automatically when the time (5hrs) is expired.
This assignment can be saved and resumed at any point until the time (5hrs) has expired.
The time will continue to run if you leave the test.
STAT 101_SEU 00967775703091 Assignment _2_2023 2_نموذج
Review Test Submission: Assignment2-STAT101- 2022-23-2nd
User
Course (Current Semester – الفصل الحالي)STAT-101: Statistics *******************
Test Assignment2-STAT101-2022-23-2nd
Started 1/27/23 11:52 PM
Submitted 1/28/23 1:55 AM
Due Date 1/30/23 11:00 PM
Status Completed
Attempt Score
9.75 out of 10 points
Time Elapsed
2 hours, 3 minutes out of 5 hours
Instructions Instructions of Assignment-2(STAT-101) The display date of Assignment 2 is Wednesday, January 25,
2023, 11:00 P.M. The due date of Assignment 2 is Monday, January 30, 2023, at
11:00 PM.
Assignment 2 covers the material of Weeks 5, 7, & 8 (Chapters-6,
7 & 8)
The assignment consists of 25 questions 10T/F (0.25 marks each) and 15MCQ (0.5marks each)
Total Marks = 10
You have only one attempt.
You have a time limit of 5 hours (300 minutes). This assignment will be saved and submitted automatically when
the time (5hrs) is expired. This assignment can be saved and resumed at any point until the
time (5hrs) has expired. The time will continue to run if you leave the test.
Good luck!
Saturday, January 28, 2023 1:56:01 AM AST
STAT 101_SEU 00967775703091 Assignment _2_2023 2_نموذج
Question 1
If the total area under standard normal probability distribution is k+1, then the value
of k is zero.
True
False
Question 2
If the z-score of normal distribution is –2.50, the mean of the distribution is 35 and the
standard deviation of normal distribution is 2, then the value of X for a normal
distribution is 40.
True
False
Question 3 Given that Z is a standard normal random variable. If P(Z > k)=0.0505, then the value of k is 1.64
True
False
Question 4
A confidence interval (or interval estimate) is a range (or an interval) of values used
to estimate the true value of a population parameter.
True
False
Question 5
The sample mean is not the best point estimate of the population mean.
True
False
Question 6
If the P-value for a one-sided test for testing a mean is 0.05, then the P-value for the
corresponding two-sided test would be 0.01.
True
False
Question 7
The probability of rejecting the null hypothesis when it is true is called Level of
significance.
True
False
Question 8
The alternative hypothesis for the following claim: “A car Company claims that its new car
will average more than 40 miles per gallon in the city” is H1: µ < 40.
True
False
STAT 101_SEU 00967775703091 Assignment _2_2023 2_نموذج
Question 9
The alternative hypothesis for the following claim: “A motorbike company claims that its new
model will give an average at least 60 km/l on a long route” is Ha: µ < 60.
True
False
Question 10
If the original claim says that the mean working hours in a day are same for men and
women in a company. Then symbolically it is represented as p1 = p2.
True
False
Question 11
You are given the following hypothesis test:
H0: μ=100
H1: μ ≠ 100 The calculated test statistic z = –1.0, and the critical value of z = ±1.97. Then, the
decision would be to:
Reject H0 since z < –1.97
Reject H0 since –1.97 < z < 1.97
Fail to reject H0 since –1.97 < z < 1.97
Fail to reject H0 since z < –1.97
Question 12
A prescription allergy medicine is supposed to contain an average of 245 parts per
million (ppm) of active ingredient. The manufacturer periodically collects data to
determine if the production process is working properly. A random sample of 64 pills
has a mean of 250 ppm with a standard deviation of 12 ppm.
Let µ denotes the average amount of the active ingredient in pills of this allergy
medicine. The null and alternative hypotheses are as H0: µ = 245, Ha:µ ≠ 245. The
level of significance is 1%.
The t-test statistic is 3.33 with a P-value of 0.0014. What is the correct conclusion?
The mean amount of active ingredient in pills of this allergy medicine is equal to 245
ppm.
The mean amount of active ingredient in pills of this allergy medicine is equal to 250
ppm.
The mean amount of active ingredient in pills of this allergy medicine is not equal to 245
ppm.
The mean amount of active ingredient in pills of this allergy medicine is greater than 245
ppm.
Question 13
Among 169 Egyptian-African men, the mean systolic blood pressure was 145 mmHg
with a standard deviation of 26. The t-test statistic to conclude that the mean systolic
blood pressure for a population of Egyptian-African men is greater than 142 is
-2.5
-1.3
1.5
-1.5
STAT 101_SEU 00967775703091 Assignment _2_2023 2_نموذج
Question 14
The degree of confidence is equal to:
1-α
β
α
1-β
Question 15
When carrying out a large sample test of H0: µ0 = 50, Ha: µ0 < 50, we reject H0 at
level of significance α when the calculated test statistic is:
Greater than zα
Less than – zα
Greater than zα/2
Less than zα
Question 16
A sample of 100 body temperatures has a mean of 98.6 oF. Assume that σ is known to
be 0.5 oF. Use a 0.05 significance level to test the claim that the mean body
temperature of the population is equal to 98.5 oF, as is commonly believed. What is
the value of test statistic for this testing?
1.0
3.0
-2.0
2.0
Question 17
With H0: μ = 100, Ha: μ < 100, the test statistic is z = – 1.75. Using a 0.05
significance level, the P-value and the conclusion about null hypothesis are (Given
that P(z < 1.75) =0.9599)
0.0401; reject H0
0.9599; fail to reject H0
0.0401; fail to reject H0
0.9599; reject H0
Question 18
A passing student is failed by an examiner, it is an example of:
Type-I error
Type-II error
Best Decision
All of above
Question 19
The confidence interval, 0.548 < p < 0.834 is obtained for a population proportion, p.
The margin of error, E using these confidence interval limits is
0.143
0.286
0.691
1.382
STAT 101_SEU 00967775703091 Assignment _2_2023 2_نموذج
Question 20
If the point estimate 𝑝 ̂ is 0.8 and the lower confidence limit is 0.6, then the upper
confidence limit is:
1.0
0.7
0.6
0.4
Question 21
If the Margin of error E is 0.5 and the upper confidence limit is 9, then the lower
confidence limit is:
10
14
8
2
Question 22 Evaluate P(-1< Z< 2), where P(Z < 2)=0.9772 and P(Z< -1)=0.1587
c. -0.1359
d. 0.8185
b. 0.1359
a. -0.8185
Question 23
The normal probability distribution curve is symmetrical about mean µ. Then P(X <
μ) = P(X > μ) is equal to
0.25
0
0.50
0.75
STAT 101_SEU 00967775703091 Assignment _2_2023 2_نموذج
Question 24 Which of the following is NOT true regarding the normal distribution?
d. The points of the curve meet the X-axis at z = –3 and z = 3
b. It has a single peak
c. It is symmetrical
a. Mean, median and mode are all equal
Question 25 Assume that the thermometer readings are normally distributed with a mean of 0°C and a standard deviation of 1°C for freezing water. If one thermometer is randomly selected, find the probability that it reads (at the freezing point of water) greater than -1.75 degrees.
a. 0.0401
b. -0.9599
c. 0.9599
d. None
,
7.1 – 2Copyright © 2010, 2007, 2004 Pearson Education, Inc. All Rights Reserved.
Lecture Slides
Elementary Statistics Eleventh Edition
and the Triola Statistics Series
by Mario F. Triola
7.1 – 3Copyright © 2010, 2007, 2004 Pearson Education, Inc. All Rights Reserved.
Chapter 7
Estimates and Sample Sizes
7-1 Review and Preview
7-2 Estimating a Population Proportion
7-3 Estimating a Population Mean: σ Known
7-4 Estimating a Population Mean: σ Not Known
7-5 Estimating a Population Variance
7.1 – 4Copyright © 2010, 2007, 2004 Pearson Education, Inc. All Rights Reserved.
Section 7-1
Review and Preview
7.1 – 5Copyright © 2010, 2007, 2004 Pearson Education, Inc. All Rights Reserved.
Review
❖ Chapters 2 & 3 we used “descriptive statistics” when we summarized data using tools such as graphs, and statistics such as the mean and standard deviation.
❖ Chapter 6 we introduced critical values: z denotes the z score with an area of to its right. If = 0.025, the critical value is z0.025 = 1.96. That is, the critical value z0.025 = 1.96 has an area of 0.025 to its right.
7.1 – 6Copyright © 2010, 2007, 2004 Pearson Education, Inc. All Rights Reserved.
Preview
❖ The two major activities of inferential statistics are (1) to use sample data to estimate values of a population parameters, and (2) to test hypotheses or claims made about population parameters.
❖ We introduce methods for estimating values of these important population parameters: proportions, means, and variances.
❖ We also present methods for determining sample sizes necessary to estimate those parameters.
This chapter presents the beginning of inferential statistics.
7.1 – 7Copyright © 2010, 2007, 2004 Pearson Education, Inc. All Rights Reserved.
Section 7-2
Estimating a Population
Proportion
7.1 – 8Copyright © 2010, 2007, 2004 Pearson Education, Inc. All Rights Reserved.
Key Concept In this section we present methods for using a
sample proportion to estimate the value of a
population proportion.
• The sample proportion is the best point
estimate of the population proportion.
• We can use a sample proportion to construct a
confidence interval to estimate the true value
of a population proportion, and we should
know how to interpret such confidence
intervals.
• We should know how to find the sample size
necessary to estimate a population proportion.
7.1 – 9Copyright © 2010, 2007, 2004 Pearson Education, Inc. All Rights Reserved.
Definition
A point estimate is a single value (or
point) used to approximate a population
parameter.
7.1 – 10Copyright © 2010, 2007, 2004 Pearson Education, Inc. All Rights Reserved.
The sample proportion p is the best
point estimate of the population
proportion p.
ˆ
Definition
7.1 – 11Copyright © 2010, 2007, 2004 Pearson Education, Inc. All Rights Reserved.
Example:
Because the sample proportion is the best point estimate of the population proportion, we conclude that the best point estimate of p is 0.70. When using the sample results to estimate the percentage of all adults in the United States who believe in global warming, the best estimate is 70%.
In the Chapter Problem we noted that in a Pew Research Center poll, 70% of 1501 randomly selected adults in the United States believe in global warming, so the sample proportion is
= 0.70. Find the best point estimate of the proportion of all adults in the United States who believe in global warming.
p̂
7.1 – 12Copyright © 2010, 2007, 2004 Pearson Education, Inc. All Rights Reserved.
Definition
A confidence interval (or interval
estimate) is a range (or an interval)
of values used to estimate the true
value of a population parameter. A
confidence interval is sometimes
abbreviated as CI.
7.1 – 13Copyright © 2010, 2007, 2004 Pearson Education, Inc. All Rights Reserved.
A confidence level is the probability 1 – (often
expressed as the equivalent percentage value)
that the confidence interval actually does contain
the population parameter, assuming that the
estimation process is repeated a large number of
times. (The confidence level is also called degree
of confidence, or the confidence coefficient.)
Most common choices are 90%, 95%, or 99%.
( = 10%), ( = 5%), ( = 1%)
Definition
7.1 – 14Copyright © 2010, 2007, 2004 Pearson Education, Inc. All Rights Reserved.
We must be careful to interpret confidence intervals correctly. There is a correct interpretation and many different and creative incorrect interpretations of the confidence interval 0.677 < p < 0.723.
“We are 95% confident that the interval from 0.677 to 0.723 actually does contain the true value of the population proportion p.”
This means that if we were to select many different samples of size 1501 and construct the corresponding confidence intervals, 95% of them would actually contain the value of the population proportion p.
(Note that in this correct interpretation, the level of 95% refers to the success rate of the process being used to estimate the proportion.)
Interpreting a Confidence Interval
7.1 – 15Copyright © 2010, 2007, 2004 Pearson Education, Inc. All Rights Reserved.
Know the correct interpretation of a confidence interval.
Caution
7.1 – 16Copyright © 2010, 2007, 2004 Pearson Education, Inc. All Rights Reserved.
Confidence intervals can be used informally to compare different data sets, but the overlapping of confidence intervals should not be used for making formal and final conclusions about equality of proportions.
Caution
7.1 – 17Copyright © 2010, 2007, 2004 Pearson Education, Inc. All Rights Reserved.
Critical Values A standard z score can be used to distinguish between sample statistics that are likely to occur and those that are unlikely to occur. Such a z score is called a critical value. Critical values are based on the following observations:
1. Under certain conditions, the sampling distribution of sample proportions can be approximated by a normal distribution.
7.1 – 18Copyright © 2010, 2007, 2004 Pearson Education, Inc. All Rights Reserved.
Critical Values
2. A z score associated with a sample proportion has a probability of /2 of falling in the right tail.
7.1 – 19Copyright © 2010, 2007, 2004 Pearson Education, Inc. All Rights Reserved.
Critical Values
3. The z score separating the right-tail region is
commonly denoted by z/2 and is referred to
as a critical value because it is on the
borderline separating z scores from sample
proportions that are likely to occur from those
that are unlikely to occur.
7.1 – 20Copyright © 2010, 2007, 2004 Pearson Education, Inc. All Rights Reserved.
Definition
A critical value is the number on the
borderline separating sample statistics
that are likely to occur from those that are
unlikely to occur. The number z/2 is a
critical value that is a z score with the
property that it separates an area of /2 in
the right tail of the standard normal
distribution.
7.1 – 21Copyright © 2010, 2007, 2004 Pearson Education, Inc. All Rights Reserved.
The Critical Value z2
7.1 – 22Copyright © 2010, 2007, 2004 Pearson Education, Inc. All Rights Reserved.
Notation for Critical Value
The critical value z/2 is the positive z value
that is at the vertical boundary separating an
area of /2 in the right tail of the standard
normal distribution. (The value of –z/2 is at
the vertical boundary for the area of /2 in the
left tail.) The subscript /2 is simply a
reminder that the z score separates an area of
/2 in the right tail of the standard normal
distribution.
7.1 – 23Copyright © 2010, 2007, 2004 Pearson Education, Inc. All Rights Reserved.
Finding z2 for a 95%
Confidence Level
-z2 z2
Critical Values
2 = 2.5% = .025
= 5%
7.1 – 24Copyright © 2010, 2007, 2004 Pearson Education, Inc. All Rights Reserved.
z2 = 1.96−+
Use Table A-2 to find a z score of 1.96
= 0.05
Finding z2 for a 95%
Confidence Level – cont
7.1 – 25Copyright © 2010, 2007, 2004 Pearson Education, Inc. All Rights Reserved.
Definition
When data from a simple random sample are
used to estimate a population proportion p, the
margin of error, denoted by E, is the maximum
likely difference (with probability 1 – , such as
0.95) between the observed proportion and
the true value of the population proportion p.
The margin of error E is also called the
maximum error of the estimate and can be found
by multiplying the critical value and the standard
deviation of the sample proportions:
p̂
7.1 – 26Copyright © 2010, 2007, 2004 Pearson Education, Inc. All Rights Reserved.
Margin of Error for
Proportions
2
ˆ ˆpq E z
n =
7.1 – 27Copyright © 2010, 2007, 2004 Pearson Education, Inc. All Rights Reserved.
p = population proportion
Confidence Interval for Estimating
a Population Proportion p
= sample proportion
n = number of sample values
E = margin of error
z/2 = z score separating an area of /2 in the right tail of the standard normal distribution
p̂
7.1 – 28Copyright © 2010, 2007, 2004 Pearson Education, Inc. All Rights Reserved.
Confidence Interval for Estimating
a Population Proportion p
1. The sample is a simple random sample.
2. The conditions for the binomial distribution
are satisfied: there is a fixed number of
trials, the trials are independent, there are
two categories of outcomes, and the
probabilities remain constant for each trial.
3. There are at least 5 successes and 5
failures.
7.1 – 29Copyright © 2010, 2007, 2004 Pearson Education, Inc. All Rights Reserved.
Confidence Interval for Estimating
a Population Proportion p
p – E < < + Eˆ p̂p
where
2
ˆ ˆpq E z
n =
7.1 – 30Copyright © 2010, 2007, 2004 Pearson Education, Inc. All Rights Reserved.
p – E < < + E
p + E
ppˆ ˆ
Confidence Interval for Estimating
a Population Proportion p
ˆ
(p – E, p + E)ˆ ˆ
7.1 – 31Copyright © 2010, 2007, 2004 Pearson Education, Inc. All Rights Reserved.
Round-Off Rule for
Confidence Interval Estimates of p
Round the confidence interval limits
for p to
three significant digits.
7.1 – 32Copyright © 2010, 2007, 2004 Pearson Education, Inc. All Rights Reserved.
1. Verify that the required assumptions are satisfied.
(The sample is a simple random sample, the
conditions for the binomial distribution are satisfied,
and the normal distribution can be used to
approximate the distribution of sample proportions
because np 5, and nq 5 are both satisfied.)
2. Refer to Table A-2 and find the critical value z /2 that
corresponds to the desired confidence level.
3. Evaluate the margin of error
Procedure for Constructing
a Confidence Interval for p
2 ˆ ˆE z pq n=
7.1 – 33Copyright © 2010, 2007, 2004 Pearson Education, Inc. All Rights Reserved.
4. Using the value of the calculated margin of error, E
and the value of the sample proportion, p, find the
values of p – E and p + E. Substitute those values
in the general format for the confidence interval:
ˆ ˆ ˆ
p – E < p < p + Eˆ ˆ
5. Round the resulting confidence interval limits to
three significant digits.
Procedure for Constructing
a Confidence Interval for p – cont
7.1 – 34Copyright © 2010, 2007, 2004 Pearson Education, Inc. All Rights Reserved.
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