8. Seventy-five percent of the students graduating from high school in a small town in Oklahoma attend college. For a random sample of 50 students from the town, what is the probability that

a. at least 80% of the surveyed students will attend college?

b. between 80% and 85% (inclusive) of the surveyed students will attend college?

please explain thought process and step by step

A local greenhouse sells coffee-tree saplings. They price their saplings based on the height of the plant. They have two workers, Susan and Karen, who measure the saplings for pricing. The greenhouse manager wants to determine if there is a significant difference in the measurements made by these two individuals. She has them measure the same set of 15 saplings. Assume that the differences are calculated as Susan – Karen.

The resulting measurements (in cm) have been saved in StatCrunch. Use the data to compute the test statistic for the difference between Susan and Karen. For help using StatCrunch for a Paired Difference T-Test click here. (You may want to right-click that link and open it in a new window so you don't lose your answers on this quiz!)

Give your answer to four decimal places.

Susan   Karen difference
51.2381   51.5426   -0.3045
49.6311   49.292   0.3391
47.4822   46.9531   0.5291
50.3223   51.2982   -0.9759
46.3025   45.7606   0.5419
50.3047   50.3377   -0.033
50.4013   51.4663   -1.065
49.6507   50.0329   -0.3822
51.0187   50.985   0.0337
51.1941   51.7125   -0.5184
47.1907   47.6407   -0.45
49.7466   49.3111   0.4355
46.5283   47.3043   -0.776
47.2727   48.1091   -0.8364
51.5522   52.2639   -0.7117

Each of three supermarket chains in the Denver area claims to have the lowest overall prices. As part of an investigative study on supermarket advertising, a local television station conducted a study by randomly selecting nine grocery items. Then, on the same day, an intern was sent to each of the three stores to purchase the nine items. From the receipts, the following data were recorded. At the 0.025 significance level, is there a difference in the mean price for the nine items between the three supermarkets? Item Super's Ralph's Lowblaw's 1 $ 1.32 $ 1.87 $ 1.25 2 1.07 1.07 2.22 3 2.46 2.46 5.05 4 2.46 2.46 2.40 5 1.14 1.14 4.15 6 1.23 1.23 4.36 7 1.37 1.37 1.80 8 1.10 1.10 3.08 9 1.29 1.29 4.36 Click here for the Excel Data File State the null hypothesis and the alternate hypothesis. For Treatment (Stores): Null hypothesis H0: μ1 ≠ μ2 ≠ μ3 H0: μ1 = μ2 = μ3 a b Alternate hypothesis H1: There is no difference in the store means. H1: There is a difference in the store means. For blocks (Items): H0: μ1 = μ2 = ... μ9 H0: μ1 ≠ μ2 ≠ ... μ9 a b Alternate hypothesis H1: There is no difference in the item means. H1: There is a difference in the item means. What is the decision rule for both? (Round your answers to 2 decimal places.) Complete an ANOVA table. (Round your SS, MS to 3 decimal places, and F to 2 decimal places.) What is your decision regarding the null hypothesis? The decision for the F value (Stores) at 0.025 significance is: Reject H0 Do not reject H0 The decision for the F value (Items) at 0.025 significance is: Reject H0 Do not reject H0 Is there a difference in the item means and in the store means?

USA Today reported that about 47% of the general consumer population in the United States is loyal to the automobile manufacturer of their choice. Suppose Ford Motor Company did a study of a random sample of 1006 Ford owners and found that 490 said they would buy another Ford. Does this indicate that the population proportion of consumers loyal to Ford is more than 47%? Make conclusions at a 10% level of significance.

a) State the hypotheses to be tested.

b) Calculate and show the test statistic by hand.

c) Calculate the p-value using tables and illustrate the p-value by providing a graph showing appropriate area under the normal curve.

d) Confirm your results using Excel. Show Output.

e) Give your conclusions in a well-written sentence.

The distribution of results from a cholesterol test has a mean of 180 and a standard deviation of 20. A sample size of 40 is drawn randomly.

Find the probability that the sum of the 40 values is less than 6,950.

Question 1.

After several semesters of research, you finally decided to launch your own product idea online. According to your web hosting service, your clients spend about 14 minutes/week on your website. You believe an increase in the average-time-spend will increase your profits. Therefore, you decided to hire a fellow student to help you with your website. Formulate your hypothesis, identify the appropriate statistical test, and develop the decision rule to determine if your classmate adds value to your website given the following data: sample size: 101, x̄: 17.9, σ: 4.6, and a confidence level of 90%.

Can you please explain the logic to concluding to the correct answer?

Answer Part 1:

Fire your fellow student

or

Keep Your fellow student

BECAUSE.....

Answer Part 2:

a. the statistics suggests that he increase the average-time-spend on you website

b. the statistics suggests that he decrease the average-time-spend on you website

c. the statistics suggests that he doesn't add any value (accept H0)

Is the magnitude of an earthquake related to the depth below the surface at which the quake occurs? Let x be the magnitude of an earthquake (on the Richter scale), and let y be the depth (in kilometers) of the quake below the surface at the epicenter. Suppose a random sample of earthquakes gave the following information.

x 2.5 4 3.4 4.4 2.4

y 5.2 10.3 10.8 10.3 8.3

Compute r.

a. 0.098

b. -0.013

c. 0.752

d. 0.013

e. -0.752

You are conducting a test of the claim that the row variable and the column variable are dependent in the following contingency table.

Give all answers rounded to 3 places after the decimal point, if necessary.

(a) Enter the expected frequencies below:

(b) What is the chi-square test-statistic for this data?
      Test Statistic: χ2=χ2=

(c) What is the critical value for this test of independence when using a significance level of αα = 0.01?
      Critical Value: χ2=χ2=  

(d) What is the correct conclusion of this hypothesis test at the 0.01 significance level?

• There is not sufficient evidence to warrant rejection of the claim that the row and column variables are dependent.
• There is not sufficient evidence to support the claim that the row and column variables are dependent.
• There is sufficient evidence to warrant rejection of the claim that the row and column variables are dependent.
• There is sufficient evidence to support the claim that the row and column variables are dependent.

Remember to give all answers rounded to 3 places after the decimal point, if necessary.

Regression Assumptions

Below are some assumptions we must meet for regression. In one or two sentences, explain what each means.

Correctly specified model?

Linearity?

Minimum multicollinearity?

Homoscedastic distribution of errors?

1.Understand how to interpret values, such as lambda, gamma, etc.

2.When is Phi appropriate?

3.When Cramer’s V appropriate?

4.What values can phi take on?

5.What if the table is larger than 2x2?

A research team conducted a study showing that approximately 15% of all businessmen who wear ties wear them so tightly that they actually reduce blood flow to the brain, diminishing cerebral functions. At a board meeting of 20 businessmen, all of whom wear ties, what are the following probabilities? (Round your answers to three decimal places.) (a) at least one tie is too tight (b) more than two ties are too tight (c) no tie is too tight (d) at least 18 ties are not too tight

a.) Given sample data: 61.2, 61.9, 62.8, 63.1, 64.0, 64.3, 64.9, 65.5, 66.3 and 67.9,
test H₀: m £ 62.89 versus H₁: m > 62.89 at a = 0.05.

b.) Test H₀: π = 0.25 versus H_A: π ¹ 0.25 with p = 0.33 and n = 100 at alpha = 0.05 and 0.10.

c.) Test at α =.05 and 0.10 the hypothesis that a majority (more than 50%) of students favor the plus/minus grading system at a university if in a random sample of 500 students, 265 favor the system?

d.) The population of lengths of aluminum-coated steel sheets is normally distributed with a mean of 30.0 inches and a standard deviation of 0.9 inches. A sample of 36 metal sheets is randomly selected from a batch. What is the probability that the average length of a sheet is between 29.82 and 30.27 inches long?

A research paper describes an experiment in which 74 men were assigned at random to one of four treatments.

1. viewed slides of fit, muscular men
2. viewed slides of fit, muscular men accompanied by diet and fitness-related text
3. viewed slides of fit, muscular men accompanied by text not related to diet and fitness
4. did not view any slides

The participants then went to a room to complete a questionnaire. In this room, bowls of pretzels were set out on the tables. A research assistant noted how many pretzels were consumed by each participant while completing the questionnaire. Data consistent with summary quantities given in the paper are given in the accompanying table.

Do these data provide convincing evidence that the mean number of pretzels consumed is not the same for all four treatments? Test the relevant hypotheses using a significance level of 0.05.

Calculate the test statistic. (Round your answer to two decimal places.)

F =

What can be said about the P-value for this test?

P-value > 0.1000.050 < P-value < 0.100    0.010 < P-value < 0.0500.001 < P-value < 0.010P-value < 0.001

What can you conclude?

Reject H₀. The data do not provide convincing evidence that the mean number of pretzels consumed is not the same for all four treatments.Fail to reject H₀. The data do not provide convincing evidence that the mean number of pretzels consumed is not the same for all four treatments.    Reject H₀. The data provide convincing evidence that the mean number of pretzels consumed is not the same for all four treatments.Fail to reject H₀. The data provide convincing evidence that the mean number of pretzels consumed is not the same for all four treatments.

You may need to use the appropriate table in Appendix A to answer this question.

Section 9.4 Practice Problems:

2. How many CSUN students would have to be polled to determine the percentage that hopes to transfer to UCLA to within 3.5% at

a. 95% confidence

b. 92% confidence

3. Suppose that a randomly chosen sample of 1024 airline travelers indicated that 624 checked a bag.

a. Check that this meets the conditions to find the 95% confidence interval.

b. What is the point estimate of the proportion of airline travelers that check a bag?

c. Find the 95% confidence interval for the proportion of all airline travelers that checked a bag.

i. Using the appropriate formula.

ii. Using the appropriate calculator function.

d. Interpret the interval in a sentence.

e. Can you say that a majority of airline travelers check a bag? Why or why not?

7. A health psychologist knew that corporate executives in general have an average score of 80 with a standard deviation of 12 on a stress inventory and that the scores are normally distributed. In order to learn whether corporate executives who exercise regularly have lower stress scores, the psychologist measured the stress of 55 exercising executives and found them to have a mean score of 72. Was there a significant reduction (at the .01 level)? a. What type of test would this be and why? (1pt) b. Show all steps for hypothesis testing and include a graph with your response.