Mathematics
Inference In Practice A Population Mean And Confidence Intervals

### Question Description

All work and explanations required

Inference in practice; Inference about a Population Mean; confidence intervals; The one-sample t confidence interval

### Unformatted Attachment Preview

Purchase answer to see full attachment

Hi, Find attached the paper for your review.Let me know if you need anything edited or changed.Looking forward to working with you again in future.Thank you.
Attached.

True/False
1. T
If you were doing a two-tailed test of significance, you would need to divide the α by two, in order to
determine the critical region.
2. T
In order to determine the y-intercept in a regression problem, both the dependent variable and the
independent variable must be quantitative.
3. T
In a random sample of 48 observations from a normal distribution, there will be approximately 12
observations less than the 25th percentile.
4. F
In a one-tailed test where n=21, the value of the Z-test statistic equals -1.812. If α were set at 0.01,
this test would be considered significant
5. F

If a person had a z-score of 0.50, then their actual raw score has to be above the median.

6. T
If a statistical test is significant at the 10% (alpha = 0.10) level, then it may or may not be significant
at the 5% (alpha = 0.05) level.
7. T
A correlation coefficient estimated to be close to +1.0 , would be considered to be a very strong
linear relationship.
8. F
If a 99% CI for the population mean age is calculated to be [36yrs, 46yrs]; then this implies that
approximately 1% of the population will be older than 46 years old.
9. T
A test of H0 : μ = 50 against H 1 : μ < 50 has test statistic t = -2.35, for n=21. This test would
be considered statistically significant at α = 0.01.
10. F
In estimating the true population mean, if you decrease the level of confidence (say 99% to 90%),
then the widthe of the CI would also decrease.
FILL IN THE BLANK (Q11- Q20) WITH A NUMBER, A WORD OR A SHORT ANSWER
11.

Using the Z-table, find the value of Z such that
P (Z < 1.645) = 0.95

--------------------------------------------------------------------------------------------------------------------------------12.
Complete the following sentence. The P-value of a test is the probability of the occurrence of a specific
event.
13.
In performing a two-tailed test for n= 18, the t-test statistic equals 2.10. If alpha = .05, what are the two
critical values from the t-table that would define the acceptance and rejection regions?
-2.567, +2.567
-------------------------------------------------------------------------------------------------------------------------------------14.
In a distribution, the mean = 158, the mode = 155 and the median = 152 and the standard deviation =12.
Which way is the distribution skewed? The distribution has a longer right tail. (Positively skewed/right skewed)
.
Why? The mean is greater than the
mode and median, thus only has a few relatively high values.

15.
Suppose age was normally distributed in a population with the mean = 62 and variance = 25. A person
whose age is 66 would have a z-score of 0.8
.
𝑍 = (𝑋 − µ) / 𝛿 = (66-62) / √25 = 0.8

.

16.

A random sample of part-time workers and the length of time (days) that they worked were recorded.
The following stem plot has a stem width of 5.
(a) ) Calculate the sample standard deviation
(b) are there any outliers? If so, what are they?
5|
5|
6|
6|
7|
7|
8|
8|
9|
9|

0
5
2
5
4
8
2
5
2
8

9
4
9
2
5
0
9

4
9
3
54
0

Std deviation = 2.996
Outliers: 0, 5 and 2
17. In recent years there has been a lot of discussion in the medical literature regarding the role of diet in the
development of heart disease. Suppose a sample of 18 individuals who eat primarily a vegetarian diet is randomly
taken. Their mean cholesterol is found to be 180 mg/dl. Suppose in the general population, the mean cholesterol is
205 mg/dl with a SD of 20mg/dl. Based on the sample data can you want to conclude that the mean cholesterol for
vegetarians is less than that of the ge...

TutorAR (16702)
University of Maryland
Review

Anonymous
The tutor managed to follow the requirements for my assignment and helped me understand the concepts on it.

Anonymous
The tutor was knowledgeable, will be using the service again.

Anonymous
Awesome quality of the tutor. They were helpful and accommodating given my needs.

Studypool
4.7
Trustpilot
4.5
Sitejabber
4.4

Brown University

1271 Tutors

California Institute of Technology

2131 Tutors

Carnegie Mellon University

982 Tutors

Columbia University

1256 Tutors

Dartmouth University

2113 Tutors

Emory University

2279 Tutors

Harvard University

599 Tutors

Massachusetts Institute of Technology

2319 Tutors

New York University

1645 Tutors

Notre Dam University

1911 Tutors

Oklahoma University

2122 Tutors

Pennsylvania State University

932 Tutors

Princeton University

1211 Tutors

Stanford University

983 Tutors

University of California

1282 Tutors

Oxford University

123 Tutors

Yale University

2325 Tutors