Statistics Question

PSYC 510Z TESTS AND SINGLE SAMPLE T -TESTS ASSIGNMENT INSTRUCTIONS
OVERVIEW
This Homework: Z-Tests & Single Sample T-Tests Assignment is designed to assess your
understanding of the concepts and applications covered thus far in this course. This module
introduces two inferential tests – the z test and single sample t test; both of which are used to
determine whether a sample differs from a population. These tests are commonly used in
psychology, education, business, and other fields. This Homework: Z-Tests & Single Sample
T-Tests Assignment assesses your knowledge, skills, applications, and presentation of these
tests using professional conventions.
INSTRUCTIONS
Be sure you have reviewed this module’s Learn section before completing this Homework: ZTests & Single Sample T-Tests Assignment. This Homework: Z-Tests & Single Sample TTests Assignment is worth 60 points. Each question is worth 3 points. Six points are awarded
for mechanics/structure.
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Part I contains general concepts from this module’s Learn section.
Part II requires use of SPSS. You will have to take screen shots and/or copy and paste from
your SPSS to place answers within this file. Make sure you only insert relevant and legible
images.
Part III is the cumulative section. These may include short answer and/or use of SPSS but
will review material from previous module(s).
Directions for each subsection are provided in the top of each table (in the blue shaded
areas).
Answers should be placed where indicated (wherever there is “ANSWER”).
Submit the file as a WORD document (.doc or .docx). Make sure the filename of your
submission includes your full name, course and section.
o Example: HW6_JohnDoe_510B01
Make sure to check the Homework Grading Rubric before beginning this Homework: Z-Tests
& Single Sample T-Tests Assignment.
Part I: General Concepts
These questions are based on the concepts covered in this module’s assigned readings
and presentations.
Answer the following questions using your own words.
1.
What is the critical value for a one-tailed z test? For a two-tailed z test? Which is more likely to
result in a rejection of the null hypothesis? Why?
ANSWER
2.
Why does tcv. Change when the sample size changes? What must be computed to determine tcv.?
ANSWER
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PSYC 510
3.
Henry performed a two-tailed test for an experiment in which N = 24. He could not find his
table of t critical values, but he remembered the tcv at df = 13. He decided to compare his tobt
with this tcv. Is he more likely to make a Type I or a type II error in this situation? Briefly
discuss why.
ANSWER
Given a population standard deviation of 12, answer the following two questions.
WORK:
ANSWER
4) Calculate the standard error of
the mean (𝝈𝐗̅ ) given the following
two sample sizes (show all your
work and round to two decimal
places):
N1 =
N2 =
N1 =
N2 =
N1 = 20
N2 = 70
5) How does the sample size change
the standard error of the mean?
What does this mean for statistical
power?
ANSWER
Calculate the critical degrees of freedom and identify the critical values for the following tests,
using p = .05 and the tables in your e-book for all scenarios (do NOT round). Then, state whether
the null hypothesis would be rejected or failed to be rejected.
6) Single sample t-test: df=
critical t =
Reject or Fail to Reject Ho:
two-tailed, N = 20, t = ANSWER
ANSWER
ANSWER
2.05
7) Single sample t-test: df=
critical t =
Reject or Fail to Reject Ho:
one-tailed, N = 20, t = ANSWER
ANSWER
ANSWER
2.05
8) Pearson’s r
df=
critical r =
Reject or Fail to Reject Ho:
correlation: two-tailed, ANSWER
ANSWER
ANSWER
N = 15, r = 0.47
9) Pearson’s r
df=
critical r =
Reject or Fail to Reject Ho:
correlation: one-tailed, ANSWER
ANSWER
ANSWER
N = 15, r = 0.47
A company decides to offer a monetary incentive for employees who log a specified
number of hours spent exercising in an attempt to improve employee health. The average
health score (higher = better) of the 75 employees who logged enough hours was 87. The
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PSYC 510
mean health score for all employees (population) was 85, with a population standard
deviation of 6.5.
10) Calculate the standard error of the mean.
11) Conduct the z-test. Show your work (use
at least two decimal places throughout).
What is the zobt score?
12) Write your conclusion using complete
sentences in APA format. Don’t forget to
include the statistical statement and whether
you reject or fail to reject the null hypothesis.
ANSWER
ANSWER
ANSWER
Part II: SPSS Application
These questions require the use of SPSS. Remember you must submit all of your work
within this word document. You will need to take a screen shot of your data view if
necessary, or copy and paste your output into the spaces below. Remember to report the
exact p value provided by SPSS output – simply reporting p.05 is not acceptable
(unless SPSS output states p=.000 – in that case you can report p