Recent incidents of food contamination have caused great concern among consumers. An article reported that 39 of 80 randomly selected Brand A brand chickens tested positively for either campylobacter or salmonella (or both), the leading bacterial causes of food-borne disease, whereas 62 of 80 Brand B brand chickens tested positive.

a)Does it appear that the true proportion of non-contaminated Brand A chickens differs from that for Brand B? Carry out a test of hypotheses using a significance level 0.01. (Use p₁ for Brand A and p₂ for Brand B.)

Calculate the test statistic and P-value. (Round your test statistic to two decimal places and your P-value to four decimal places.)

z=  P-value =

b)if the true proportions of non-contaminated chickens for the Brand A and Brand B are 0.50 and 0.25, respectively, how likely is it that the null hypothesis of equal proportions will be rejected when a 0.01 significance level is used and the sample sizes are both 60? (Round your answer to four decimal places.)

A supermarket is trying to decide whether to accept or reject a shipment of tomatoes. It is impossible to check all the tomatoes for size, but they desire an average weight of 8 ounces (they neither want too large nor too small).

(a) State the hypotheses.

(b) A random sample of 25 tomatoes yields an average weight of 7.65 ounces and a standard

deviation of 1.15 ounces. Calculate the test statistic and the p-value.

(c) Would you reject H0, or fail to reject H0 at 5% level of significance?

(d) Should the supermarket reject the shipment? Explain.

(e) To what type of error are you subject to?

Collect data from 30 people from your work, school, neighborhood, family, or other group. Ask a quantitative question, such as, “How many pets do you have?” or “How many college classes have you taken?” Explain your population, sample, and sampling method and what level of measurement your data is (nominal, ordinal, interval, or ratio). Use technology ( Excel) to create a Histogram of your data and explain the shape of the distribution (bell-shaped, uniform, right-skewed, or left-skewed) and possible reasons why the distribution is this shape. Explain the importance of this data, what you find interesting about the data, and why the public should know. Look up a newspaper, e-pub, or journal article that confirms or denies the results of your small study.

Please explain briefly.

7. A certain drug is used to treat asthma. In a clinical trial of the​ drug, 20 of 286 treated subjects experienced headaches​ (based on data from the​ manufacturer). The accompanying calculator display shows results from a test of the claim that less than 12​% of treated subjects experienced headaches. Use the normal distribution as an approximation to the binomial distribution and assume a 0.05 significance level to complete parts​ (a) through​ (e) below.

a. Is the test​ two-tailed, left-tailed, or​ right-tailed?

Right tailed test

​Left-tailed test

​Two-tailed test

b. What is the test​ statistic?

Z=

​(Round to two decimal places as​ needed.)

c. What is the​ P-value?

​P-value=______

​(Round to four decimal places as​ needed.)

d. What is the null​ hypothesis, and what do you conclude about​ it?

Identify the null hypothesis.

A:Ho<0.09

B:Ho>0.09

C:Ho:p≠0.09

D:Ho:p=0.09

Decide whether to reject the null hypothesis. Choose the correct answer below.

A.Reject the null hypothesis because the​ P-value is greater than the significance​ level, alpha.

B.Reject the null hypothesis because the​ P-value is less than or equal to the significance​ level, alpha.

C.Fail to reject the null hypothesis because the​ P-value is greater than the significance​ level, alpha.

D.Fail to reject the null hypothesis because the​ P-value is less than or equal to the significance​ level, alpha.

e. What is the final​ conclusion?

A.There is not sufficient evidence to support the claim that less than 9​% of treated subjects experienced headaches.

B.There is not sufficient evidence to warrant rejection of the claim that less than 9​% of treated subjects experienced headaches.

C.There is sufficient evidence to warrant rejection of the claim that less than 9​% of treated subjects experienced headaches.

D.There is sufficient evidence to support the claim that less than 9​% of treated subjects experienced headaches.

Suppose μ₁ and μ₂ are true mean stopping distances at 50 mph for cars of a certain type equipped with two different types of braking systems. The data follows: m = 8,x = 115.8, s₁ = 5.06, n = 8, y = 129.5, and s₂ = 5.35. Calculate a 95% CI for the difference between true average stopping distances for cars equipped with system 1 and cars equipped with system 2. (Round your answers to two decimal places.)

A machine that is programmed to package 3.90 pounds of cereal is being tested for its accuracy. In a sample of 64 cereal boxes, the sample mean filling weight is calculated as 3.95 pounds. The population standard deviation is known to be 0.14 pound. [You may find it useful to reference the z table.]

a-1. Identify the relevant parameter of interest for these quantitative data.

The parameter of interest is the average filling weight of all cereal packages.
The parameter of interest is the proportion filling weight of all cereal packages.

a-2. Compute its point estimate as well as the margin of error with 90% confidence. (Round intermediate calculations to at least 4 decimal places. Round "z" value to 3 decimal places and final answers to 2 decimal places.)

b-1. Calculate the 90% confidence interval. (Use rounded margin of error. Round your final answers to 2 decimal places.)

b-2. Can we conclude that the packaging machine is operating improperly?

No, since the confidence interval contains the target filling weight of 3.90.
No, since the confidence interval does not contain the target filling weight of 3.90.
Yes, since the confidence interval contains the target filling weight of 3.90.
Yes, since the confidence interval does not contain the target filling weight of 3.90.

c. How large a sample must we take if we want the margin of error to be at most 0.02 pound with 90% confidence? (Round intermediate calculations to at least 4 decimal places. Round "z" value to 3 decimal places and round up your final answer to the next whole number.)

Problem 1

The dependent variable is assumed to be values of a land.

a) Use the Excel regression tool to do the linear regression, and provide the

“Line Fit Plots” (which is provided in the regression interface). (5 points)

b) What can the plot tell you? E.g., does it show that the fitting is good?

(5 points)

c) Now check the output.

c.1) What is the standard error of the estimate of the slope? (5 points)

c.2) What is the t-test statistic for the slope? Reproduce the t-test statistic

in Excel using other values in the output (e.g., point estimate and standard

error). (10 points)

c.2) What is the 95% confidence interval of the slope? Reproduce the con-

fidence interval in Excel using other values in the output (e.g., t stat). Can

we use the confidence interval to claim that the independent variable can be

dropped in the linear regression model? (10 points)

c.3) What is the p-value for the estimate of the slope? Reproduce the p-value

in Excel using other values in the output (e.g., t stat). Can we use the p-values

to claim that the independent variable can be dropped in the linear regression

model? (10 points)

c.4) Does the linear regression model fit well? Explain your answer. (5

points)

d) Assume that the area of the land you are considering to sell is only one

acre. Does the linear regression model provide a good prediction for the value

of your land? (5 points)

e) Assume that you want to check if the slope should be significantly bigger

than 10,000.

e.1) Write the hypotheses. (5 points)

e.2) What is the new t-test statistic? (5 points)

e.3) What is the new p-value for the estimate of the slope? Is the slope

significantly bigger than 10,000? (10 points)

5. The test statistic of z=2.31 is obtained when testing the claim that p>0.3.

a. This is a (two-tailed, right-tailed, left-tailed) test.

b.​ P-value=_____

​(Round to three decimal places as​ needed.)

Choose the correct conclusion below.

A.Reject Ho. There is sufficient evidence to support the claim that p>0.3.

B.Reject Ho. There is not sufficient evidence to support the claim that p>0.3.

C.Fail to reject Ho. There is sufficient evidence to support the claim that p>0.3.

D.Fail to reject Ho. There is not sufficient evidence to support the claim that p>0.3

6. The test statistic of z=- 2.58 is obtained when testing the claim that P=3/5.

a. The critical​ value(s) is/are z=______

​(Round to two decimal places as needed. Use a comma to separate answers as​ needed.)

b. Choose the correct conclusion below.

A.Reject Ho. There is not sufficient evidence to warrant rejection of the claim that P=3/5

B.Reject Ho. There is sufficient evidence to warrant rejection of the claim that P=3/5

C.Fail to reject Ho. There is sufficient evidence to warrant rejection of the claim that P=3/5

D.Fail to reject Ho. There is not sufficient evidence to warrant rejection of the claim that P=3/5

Bass - Samples: The bass in Clear Lake have weights that are normally distributed with a mean of 2.2 pounds and a standard deviation of 0.6 pounds. Suppose you catch a stringer of 6 bass with a total weight of 15.9 pounds. Here we determine how unusual this is.

(a) What is the mean fish weight of your catch of 6? Round your answer to 1 decimal place.


(b) If 6 bass are randomly selected from Clear Lake, find the probability that the mean weight is greater than the mean of those you caught. Round your answer to 4 decimal places.
2

(c) Which statement best describes your situation?

This is unusual because the probability of randomly selecting 6 fish with a mean weight greater than or equal to the mean of your stringer is less than the benchmark probability of 0.05.

This is not particularly unusual because the mean weight of your fish is only 0.5 pounds above the population average.

-PLEASE SHOW ALL WORK-

For this problem, carry at least four digits after the decimal in your calculations. Answers may vary slightly due to rounding.

A random sample of medical files is used to estimate the proportion p of all people who have blood type B.

(i) If you have no preliminary estimate for p, how many medical files should you include in a random sample in order to be 85% sure that the point estimate p̂ will be within a distance of 0.03 from p? (Round your answer up to the nearest whole number.)

_______ medical files

(ii) Answer part (i) if you use the preliminary estimate that about 11 out of 90 people have blood type B.

_______ medical files

Explain the difference between coorelational, quasi-experimental, and true-experimental designs.

Define confidence belt and credible set. What is the confidence interval and credible probabilities?

Please describe your experience with professional grant writing or publishing your work in peer reviewed journals

What is the Wilcoxon rank test and when do you use it. What are the advantages  and disadvantages of this test.?