[lwandle2000]

Continuous data
A sample of 17 states had these cigarette taxes (in cents):
112 120 98 55 71 35 99 124 64 150 150 55 100 132 20 70 93

Find a 95% confidence interval for the cigarette tax in all 50 states.

Source: Federation of Tax Administrators

A. Construct a 95% confidence interval for the population mean.
(You will need summary data for the Excel calculator. Calculate the sample mean (Xbar) and the sample standard deviation (s))

1. What was the Point Estimate?

2. What was the Margin of error, E =

3. What was the t-value?

4. Confidence Interval?
(write as 23 < µ < 45)


B. What does it mean?
1. Interpret the confidence interval results in statistical talk.

2. How would you explain the results in plain talk to your boss, spouse, or friend who is not a statistician.


Attach the Excel worksheet with the calculations.

survey of 200,000 boat owners found that 12% of the pleasure boats were named Serenity. Find the 95% confidence interval of the population proportion of boats named Serenity at 95% confidence level.

Source: USA TODAY Snapshot.

A. Construct a interval for the proportion of all pleasure boats that were named Serenity.
1. What was the Point Estimate?

2. What was the Margin of error, E =

3. What was the z-value?

4. Confidence Interval?
(write as 0.089 < µ < 0.125)


C. Interpret the confidence interval.


D. Check the normality assumption

A job placement director claims that the average starting salary for nurses is $24,000. A sample of 10 nurses' salaries has a mean of $23,450 and a standard deviation of $400.

RQ: Is the average starting salary for nurses at $24,000 with a 95% confidence level?

A. Before starting the calculations... In plain talk, what do you hope to learn from using this hypothesis test?


B. Choose the Hypothesis


C. Specify the Decision Rule & Critical value


D. Calculate the Test Statistic


E. Make the Decision


F. Give an interpretation of the Decision


G. P-value Method
Learning to use the P-value method will save considerable time from having to determine the critical value.
1.What is the P-value (MegaStat calculates this value)?


2. Does that P-value support the Decision in Part E? Explain.



Attach your Excel document with the (MegaStat preferred) calculation.

An attorney claims that more than 25% of all lawyers in his city advertise. A sample of 200 lawyers in his city showed that 63 had used some form of advertising.

RQ: Is there enough evidence to support the attorney's claim that lawyers advertise more than 25% in his city at a 95% confidence level?

A. Choose the Hypothesis


B. Specify the Decision Rule


C. Calculate the Test Statistic


D. Make the Decision


E. Give an interpretation of the Decision


F. P-value Method
1. What was the P-value?

2. Does that P-value support the Decision in Part D? Explain.

Please attach your Excel worksheet with (MegaStat preferred) calculation.

Central Tendency

A. How is a Population Mean (µ) different from a Sample Mean (Xbar)? Provide an example of each in terms of something that you are familiar with.

B. What is a Median? When is this is a useful measure over using the mean?


Dispersion

C. How is a Population Standard Deviation (σ) different from a Sample Standard Deviation (s)? Consider the calculation aspect.

D. Briefly define the Interquartile range (IQR) and when it might be used instead of standard deviation?


Skewness

E. Skewness may be caused by lopsided data (data favoring one side of the mean), or from outliers, or both.
1. Give an personal example of when lopsided data may be encountered.

2. Give an example of data that has extreme outliers.


F. What precautions would you remind a colleague when he or she is interpreting data that has a significant skew? In regards to:
1. Central Tendency

2. Dispersion

Brief Scenario: An upcoming homeowner's association election is being held in a couple days. The Galluping Pollsters took a sample last week, and determined the following:

The candidates:
Bugsy Rabbit 48%
Elmer Fuddruckers 52%
Margin of error +/-3%

A. Point estimate
1. Define point estimate.


2. What is the point estimate for Bugsy?
(No math involved)


B. What is the confidence interval for:
(No math involved, express as: point estimate +/- margin of error)
1. Elmer?

2. Bugsy?


C. What does it mean for Bugsy's and Elmer's confidence interval to overlap?


D. Who has the greatest chance of winning if elections were held tonight? Explain.
(Consider when the poll was taken & overlapping confidence interval)

+ Hypothesis Direction
a. Two-tail, (Ho: µ = ; H1: µ )
b. One-tail, Left (Ho: µ ≥ ; H1: µ < )
c. One-tail, Right (Ho: µ ≤ ; H1: µ > )

Instructions
+ Read the Research Question (RQ).
+ What is the direction? a. b. or c. (See above)
+ What word was the directional cue?

Typical RQs for One-Sample Hypothesis Test (will be seen in Week 1 Activities)

A. RQ: Is Crosset's experience different from that claimed by the manufacturer?
Direction:
Directional cue:

B. RQ: Can we conclude that a larger proportion of students at your high school have jobs?
Direction:
Directional cue:

C. RQ: Can we conclude that the assembly time using the new method is faster?
Direction:
Directional cue:

Typical RQs for Two-Sample Hypothesis test (will be seen in Week 2 Activities)

D. RQ: Can we conclude that babies using Gibbs brand have gained less weight?
Direction:
Directional cue:

E. RQ: Is there a significant difference in the proportions of single and married persons having an accident during a three-year period?
Direction:
Directional cue:

F. RQ: Is it reasonable to conclude that the mean weekly salary of nurses is higher than school teachers?
Direction:
Directional cue:

G. RQ: Has there been a decrease of crimes since the inauguration of the program?

The legitimacy of the study is not the question. The information comes by a medical reporter who has made a research article more readable for the public.

Study: Eggs and Your Health

RQ: Does eating eggs increase a person's blood serum cholesterol?

Dependent Variable: Cholesterol level
Independent Variable: Egg eaters

Five-hundred subjects participated in a (longitudinal) study that lasted for two years. The participants were randomly assigned to either a no-egg group or to a moderate-egg group. The blood serum cholesterol levels were checked at the beginning and at the end of the study. Overall, the groups' levels were not significantly different. The company reminds us that eating eggs is healthy if done in moderation. Many of the previous studies relating eggs and high blood serum cholesterol jumped to improper conclusions (Bluman, 2007).


A. Who were the potential population of this study?


B. How do you know if a sample was collected?


C. What was the hypothesis?


D. What data was collected?


E. What there statistical significance?





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[Fr_Chuck]

I have merged your posts, we don't do your homework here. So please don't ask homework here.