The following relative frequency distribution was constructed from a population of 650. Calculate the population mean, the population variance, and the population standard deviation.

Population Mean -

Population Variance -

Population Standard Deviation -

Define each and provide an example.

-1 Convenience Sample

-2 Cross-sectional research design

-3 Research Ethics

-4 Randomization “ Data Collection”

You have colleagues who reside in different zip codes. Which measure(s) of central tendency or other descriptive statistics would you use to describe this information? (please answer in full paragraphs - thank you)

A recent debate about where in the United States skiers believe the skiing is best prompted the following survey. Using α = 0.10, test to see if the best ski area is independent of the level of the skier. Write the hypotheses, calculate the expected counts, check the condition, calculate the test statistic, and use either the critical value approach or the p-value approach to make a conclusion.

Level of the Skier
U.S. Ski Area Beginner Intermediate Advanced
Tahoe 20 30 40
Utah 10 30 60
Colorado 10 40 50

A researcher was interested in the effects of alcohol on attractiveness of mate selected (referred to as the beer goggle effect). She compared the rating (by independent raters) on level of attractiveness of the partners that young people chose at a party. She compared a group before using alcohol then after using alcohol. Assessment was whether their chosen partners differed in levels of attractiveness. Higher scores indicated more attractive partners. The attractiveness of partner for each participant (measured by independent raters) in 2 scenarios for the same group (before using alcohol and after using alcohol) was as follows:

1. Test the hypothesis (Use alpha level of 0.05) using both manual and MS Excel calculations that there is no statistically significant difference between alcohol using and non-alcohol using group with regard to the level of attractiveness of the partners they chose by the end of the party. In your answer determine and interpret the strength of this relationship.

Think of a problem that you may be interested in that deals with a comparison of two population means. Propose either a confidence interval or a hypothesis test question that compares these two means. Gather appropriate data and post your problem (without a solution) in the discussion topic. Later, respond to your own post with the solution for others to check their work.

For example, you may want to know if the average weight of a rippled potato chip is the same as the average weight of a non-rippled potato chip. You may weigh rippled regular potato chips from a large bag and find weights of 1.7, 1.9, 2.4, 1.3, 1.7, and 2.0 grams. You may weigh non-rippled potato chips from another large bag and find weights of 1.8, 1.6, 1.9, 1.9, and 1.4 grams. Assume a random sample was drawn.

The evidence supporting obesity as a risk factor for colon cancer remains inconclusive, especially among women. A study reported the association between obesity (measured at baseline) and colon cancer morbidity as determined from review of medical records and death certificates in a nationally representative cohort of men and women age 25-74 years who participated in the First National Health and Nutrition Examination Survey from 1971 to 1975 and were subsequently followed up through 1992. The following table is from this study for men and women combined.

a. Which of the following best describes the research design used in this study? Choose the ONE best answer. (1 point)

1. Cross-sectional survey
2. Ecological study
3. Population based case control study
4. Cohort study
5. None of the above

b. Complete the table above by calculating the crude body mass index-specific incidence rates. (Show your work in the table above.) (3 points – ½ point for each correct answer)

c. Calculate the relative risk (rate ratio) of colon cancer associated with a BMI of 30+. Use the lowest BMI category as the reference group. In one sentence interpret your answer. (2 points)

d. Calculate the attributable fraction among those in the 30+ BMI category. In one sentence interpret your answer. (The attributable fraction formulas provided in class can be used even though the data provided here is for rates.) (2 points)

Outline the best clustering method for the following tasks (and briefly describe the reason you would make such a design) :

(a) Finding oil spills along a coast line.

(b) Clustering employees in a company based on their salaries and years of working experience.

There is a strong linkage between statistical data analysis and data mining. Some people think of data mining as automated and scalable methods for statistical data analysis. Do you agree or disagree with this perception? Present one statistical analysis method that can be automated and/or scaled up nicely by integration with current data mining methodology.

You are a news vendor selling the FTU Daily Times every morning. Before you get to work, you go to the printer and buy the day’s paper for $0.35 a copy. You sell a copy of the Sun Times for $1.20. Daily demand is distributed normally with mean = 300 and standard deviation = 75. At the end of each morning, any leftover copies are worthless and they go to a recycle bin. How many copies of the FTU Times should you buy each morning? Based on part (a), what is the probability that you will run out of stock?

What are the major differences among the three methods for the evaluation of the accuracy of a classifier:

(a) hold-out method,

(b) cross-validation, and

(c) bootstrap?

The publisher of a sports magazine plans to offer new subscribers one of three gifts: a sweatshirt with the logo of their favorite team, a coffee cup with the logo of their favorite team, or a pair of earrings with the logo of their favorite team. In a sample of 500 new subscribers, the number selecting each gift is reported below. At the .05 significance level, is there a preference for the gifts or should we conclude that the gifts are equally well liked?

A bakery opens every day from Monday to Saturday, but only in the morning
on Wednesdays. It is known that the number of bread rolls sold daily follows
a Gaussian distribution with mean 130 and standard deviation 20 with the
exception of Wednesdays for which the distribution of the number of bread
rolls sold is still Gaussian but with mean 100 and standard deviation 30.
(a) What is the probability that on a Wednesday the bakery will sell more
than 140 bread rolls?
(b) What is the probability that on a random opening day the bakery will
sell more than 140 bread rolls?
(c) What is the probability that in a week the bakery will sell more than
800 bread rolls?

Define data processing and explain the steps to be followed for data processing

You’re a researcher looking at whether or not applicants are accepted to a prestigious law internship. Only 10% of applicants receive a call to a first interview. You’re interested in two samples: all students from a rural community college who applied (24) and all students from Arizona who applied over the last five years (5804).

What are the mean and standard deviation for the large sample?

Explain in the context of this scenario what the mean represents, with appropriate rounding and units.

For the large sample, what is the probability that at least 600 students in the past five years received a first call?