Match each example to the type of bias that would result

3. Load the dataset called ec122a.csv and decide the appropriate regression to run. Write down what transformations, corrections, etc... you make and why.

please show all work

A travel agent wants to estimate the proportion of vacationers who plan to travel outside the United States in the next 12 months. A random sample of 130 vacationers revealed that 40 had plans for foreign travel in that time frame. Construct a 95% confidence interval estimate of the population proportion. Make a statement about this in context of the problem

The number of goods sold by “The Local” is in excess of one million per year with deliveries being about 40% of that figure. The amount of goods sold has decreased marginally in recent years. “The Local” is wholly owned but Bianca and her staff have a standard of living to maintain so there is some pressure to raise overall sales whilst keeping costs, particularly delivery costs, in check.     Bianca continues: It is your job to use the sample data from last year’s overall sales to do some statistical analyses and interpretations, investigating what the current overall sales of the business are and providing insights that will guide future business decisions.

Below is last years overall sales vs deliveries data.

1. Please identify the qualitative and quantitative discrete, continuous varibles?

2. Is it cross sectional or time series data?

3. How do you calculate z scores and which are outliers?

4. How do you calculate the covariance and correlation and what does it mean?

The table shows the results of a survey in which 142 men and 145 woman workers age 25 to 64 were asked if they have at least one months income set aside for emergencies. Complete parts a-d. a.) Find the probability that a randomly selected worker has one months income or more set aside for emergencies. b.) Given that a randomly selected worker is male find the probability that the worker has less than one months income. c.) Given that a randomly selected woker has one months income or more, find the probablitly that the worker is female. d.) Are the events "having less than one months income saved" and "being male" independant?

Researchers for an advertising company are interested in determining if people are more likely to spend more money on beer if advertisers put more beer ads on billboards in a neighborhood in Philadelphia. They estimate that 250 people will view their billboard in one week. They determine that the total number of residents in the neighborhood is 600. So, the residents who have not viewed the billboard are in the control group. The researchers determine that those who did view the ads spent $24 per week on beer and those who did not view the ads spent $16 per week on beer.

1. Calculate the treatment effect.

2. Calculate the standard error (hint: the researchers determined the Std. Dev. for the control is $1.3 and the Std. Dev. for the treatment is $0.90)

3. Calculate the t-statistic.

4. Can we reject OR fail to reject the null hypothesis? Explain why.

SELECT a simple random sample size 37 from the cereal data. Outline in detail the process you used and identify the fist 4 members of your example.

- Use the variable Mfr for this sample of 37 to answer each of the following.

(a). identify the variable of interest along with the level of measure.

(b) CONSTRUCT a frequency table for the data.

(c) Display the data in a graph. Be sure to include all the proper labels in the graph.

(d) describe the shape of the data if it is appropiate to do so. If it is not appropiate to describe the shape then explain why.

The types of browse favored by deer are shown in the following table. Using binoculars, volunteers observed the feeding habits of a random sample of 320 deer.

Use a 5% level of significance to test the claim that the natural distribution of browse fits the deer feeding pattern.

(a) What is the level of significance?

State the null and alternate hypotheses.

H₀: The distributions are different.

H₁: The distributions are different.

H₀: The distributions are different.

H₁: The distributions are the same.    

H₀: The distributions are the same.

H₁: The distributions are the same.

H₀: The distributions are the same.

H₁: The distributions are different.

(b) Find the value of the chi-square statistic for the sample. (Round the expected frequencies to at least three decimal places. Round the test statistic to three decimal places.)

Are all the expected frequencies greater than 5?

Yes

No    

What sampling distribution will you use?

chi-square

binomial    

normal

uniform

Student's t

What are the degrees of freedom?

(c) Estimate the P-value of the sample test statistic.

P-value > 0.100

0.050 < P-value < 0.100    

0.025 < P-value < 0.050

0.010 < P-value < 0.025

0.005 < P-value < 0.010

P-value < 0.005

(d) Based on your answers in parts (a) to (c), will you reject or fail to reject the null hypothesis that the population fits the specified distribution of categories?

Since the P-value > α, we fail to reject the null hypothesis.

Since the P-value > α, we reject the null hypothesis.    

Since the P-value ≤ α, we reject the null hypothesis.

Since the P-value ≤ α, we fail to reject the null hypothesis.

(e) Interpret your conclusion in the context of the application.

At the 5% level of significance, the evidence is sufficient to conclude that the natural distribution of browse does not fit the feeding pattern.

At the 5% level of significance, the evidence is insufficient to conclude that the natural distribution of browse does not fit the feeding pattern

Problem 6.
1. If X N(9; 4), nd Pr(jX ? 2j < 4).
2. If X N(0; 1), nd Pr(jX + 3j > 5).
3. If X N(?2; 9), nd the number c such that Pr(jX + 2j < c) = 0:5.

A device is used in many kinds of systems. Assume that all systems have either 1, 2, 3, or 4 of these devices and that each of these four possibilties is equally likely to be the case. Each device in a system has probablility = 0.1 of failing, and the devices function independently of one another. This implies that once we know how many devices are present, the probability distribution of the number of failures will be known. E.g. if a system employs 3 of the devices, then the number that fail will have a binomial distribution with parameters n = 3 and p = 0.1

Denote with X, the number of failures of devices in the system, and with Y, the total number of devices in the system. What is observed is that for b = 1,2,3, and 4, the conditional probability mass function is the binomial probability mass function with parameters n = b, and p = 0.1

a) Find the joint probability mass table of P(X,Y)

The following random sample of weekly student expenses in dollars is obtained from a normally distributed population of undergraduate students with unknown parameters.

You have been charged to conduct a statistical test in SPSS to verify the claim that the‘average weekly student expenses’ is different than 74 dollars using an alpha level of 5%.

What is the appropriate test that is applicable in this case. Explain your reasoning.

State the null and alternate hypotheses in this case using proper statistical notations.

List one assumption that you are making about the distribution.

Insert a copy of the summary table of descriptive statistics generated in SPSS.

Insert a copy of the table for the statistical test you conducted in SPSS.

Drawing on information from the tables in (e) and/or (f) show how they relate to t-statistic as obtained in SPSS.

What is/are the critical value(s) of the test statistic at the 5% significance level.

What can you conclude about the claim based on the results generated from the statistical test? Make sure to support your conclusion by referencing the appropriate statistics from the test.

Compute the 90% confidence interval for the average weekly expenses.

Compute the Cohen’s d effect size.

​It's tough to find out how much people​ earn, but in​ 2011, a magazine reported that the average​ lawyer's salary in a country was $64,000. Suppose that today you interview a random sample of 55 lawyers in the country and find that the average salary is $75,275​, with a standard deviation of $82,694.Do you think the average​ lawyer's salary today is higher than that reported by the magazine in​ 2011? For this​ problem, assume alphaαequals=0.05.

Let muμ be the population mean​ lawyer's salary in the country.

Determine the null and alternative hypotheses.

H0 : u = 64,000

HA : u > 64,000

Test statistic is 1.01

What is the P-Value?

Suppose a 90% confidence interval for the mean salary of college graduates in a town in Mississippi is given by [$45,783, $57,017]. The population standard deviation used for the analysis is known to be $13,700. [You may find it useful to reference the z table.]

a. What is the point estimate of the mean salary for all college graduates in this town?

b. Determine the sample size used for the analysis. (Round "z" value to 3 decimal places and final answer to the nearest whole number.)

You read in the results section of an article in a psychology journal that the results of at-test for independent sample means revealed a significant t12 = 1.8, with σˆX1−X2 = 2. If there were 8 participants in the experimental group,

(a) how many participants were in the corresponding control group?

(b) what significance level was used, and was the test a one-tailed or a two-tailed test?

(c) what was the mean difference between the experimental and the control groups?