For each of the following exercises 1 to 4: For each test use either the critical value or the P-value method you are not required to use both.

1. State the claim and the hypothesis.
2. Find the critical value(s) and describe the critical (rejection) region You can choose to use the P-value method in this case state the P-value after the test value.
3. Compute the test value (statistic)
4. Make a decision
5. Summarize the results (conclusion

The department of transportation in a particular city knows from past records that 27% of workers in the downtown district use the subway system each day to commute to and from work (that is 27 success out of 100 trials). The department suspects that this proportion has increased owing to decreased parking spaces in the downtown district. A random sample of 130 workers in the downtown district showed that 49 used the subway daily. Test the claim at the 5% level of significance.

A researcher is interested in examining whether there are differences in students’ sense of safety across schools. She selects three schools and surveys five students from each school. The tab labeled Question 3 reflects the answers from this survey—the higher the score, the safer the student feels. Is there a difference between these schools in the students’ sense of safety?

a. What is the null hypothesis?

b. What is the research hypothesis?

c. Why run an ANOVA statistical test?

d. What are the results of the hypothesis test? Interpret your findings. Can you reject the null hypothesis?

Chapter 10 - 32

The post anesthesia care area (recovery room) at St. Luke’s Hospital in Maumee, Ohio, was recently enlarged. The hope was that the change would increase the mean number of patients served per day to more than 25. A random sample of 15 days revealed the following numbers of patients.

1 In a research report from an experiment, the term a statistically significant difference is used to indicate ____________ .

• A. that the there is a very low probability (i.e., 5% or less) the difference obtained in the study could happen by chance
• B. that the there is a high probability (i.e., 95% or more) the difference obtained in the study could happen by chance
• C. that the difference is large
• D. b & c

2 determining a person’s height would involve measurement on a(n) __________ scale.

• A. ratio
• B. interval
• C. ordinal
• D. nominal

3 A research report describing the results of a repeated-measures study states, "The data showed a significant difference between treatments, t(22) = 4.91, p < 0.05” From this report you can conclude that the outcome of the hypothesis test was ______________.

• A. to reject the null hypothesis and that indicates that the treatment had no effect.
• B. It is impossible to determine whether or not the null hypothesis was rejected from the information given.
• C. to fail to reject the null hypothesis and that indicates that the treatment had no effect.
• D. to fail to reject the null hypothesis and that indicates that the treatment did produce a significant effect on participants ‘behavior.
• E. to reject the null hypothesis and that indicates that the treatment did produce a significant effect on participants’ behavior.

4 If the researchers of the experiment described in question 11 committed Type I error in hypothesis testing that would mean ______. .

• A. they falsely concluded that having breakfast has a significant effect on math test scores.
• B. they correctly concluded that having breakfast has a significant effect on math test scores.
• C. they falsely concluded that having breakfast has no effect on math test scores.
• D. None of the above.

5 If the researchers of the experiment described in question 11 committed Type I error in hypothesis testing that would mean ______. .

• A. they falsely concluded that having breakfast has a significant effect on math test scores.
• B. they correctly concluded that having breakfast has a significant effect on math test scores.
• C. they falsely concluded that having breakfast has no effect on math test scores.
• D. None of the above.

6 A sample has the mean of M = 50 and the standard deviation of s = 9. If you randomly select a single score from this sample, on the average, how close would it be to the sample mean? (Hint: what is measured by standard deviation?)

• A. Within 9 points above or below the mean.
• B. Within 5 points above or below the mean.

• C. Within 3 points above or below the mean.

• D. Can’t determine from the information given.

One objectiveOne objective of this course is learning how to correctly interpret statistical measures. This includes learning how to identify intentionally misleading statistics. For this week's activity create your own example of a misleading statistic. Explain the context of the data, the source of the data, the sampling method that you used (or would use) to collect the data, and the (misleading) conclusions that would be drawn from your example. Be specific in explaining how the statistic is misleading. of this course is learning how to correctly interpret statistical measures. This includes learning how to identify intentionally misleading statistics. For this week's activity create your own example of a misleading statistic. Explain the context of the data, the source of the data, the sampling method that you used (or would use) to collect the data, and the (misleading) conclusions that would be drawn from your example. Be specific in explaining how the statistic is misleading.

You wish to test the following claim (HaHa) at a significance level of α=0.05α=0.05. For the context of this problem, one data set represents a pre-test and the other data set represents a post-test.     

Ho:μd=0Ho:μd=0
Ha:μd≠0Ha:μd≠0

You believe the population of difference scores is normally distributed, but you do not know the standard deviation. You obtain pre-test and post-test samples for n=137n=137 subjects. The average difference (post - pre) is ¯d=2.2d¯=2.2 with a standard deviation of the differences of sd=43.1sd=43.1.

1. What is the test statistic for this sample?
   
   test statistic =  Round to 4 decimal places.
   
2. What is the p-value for this sample? Round to 4 decimal places.
   
   p-value =  
   
3. The p-value is...
   • less than (or equal to) αα
   • greater than αα
   
   
4. This test statistic leads to a decision to...
   • reject the null
   • accept the null
   • fail to reject the null
   
   
5. As such, the final conclusion is that...
   • There is sufficient evidence to warrant rejection of the claim that the mean difference of post-test from pre-test is not equal to 0.
   • There is not sufficient evidence to warrant rejection of the claim that the mean difference of post-test from pre-test is not equal to 0.
   • The sample data support the claim that the mean difference of post-test from pre-test is not equal to 0.
   • There is not sufficient sample evidence to support the claim that the mean difference of post-test from pre-test is not equal to 0.

SCENARIO 12-7

Data on the percentage of 200 hotels in each of the three large cities across the world on whether minibar charges are correctly posted at checkout are given below.

At the 0.05 level of significance, you want to know if there is evidence of a difference in the proportion of hotels that correctly post minibar charges among the three cities.


Referring to Scenario 12-7, the expected cell frequency for the Hong Kong/Yes cell is ________.

The types of raw materials used to construct stone tools found at an archaeological site are shown below. A random sample of 1486 stone tools were obtained from a current excavation site. Raw Material Regional Percent of Stone Tools Observed Number of Tools as Current excavation Site Basalt 61.3% 914 Obsidian 10.6% 159 Welded Tuff 11.4% 173 Pedernal chert 13.1% 195 Other 3.6% 45 Use a 1% level of significance to test the claim that the regional distribution of raw materials fits the distribution at the current excavation site. (a) What is the level of significance? State the null and alternate hypotheses. H0: The distributions are the same. H1: The distributions are the same. H0: The distributions are the same. H1: The distributions are different. H0: The distributions are different. H1: The distributions are the same. H0: The distributions are different. 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 Student's t uniform normal binomial What are the degrees of freedom? (c) Find or 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 of independence? 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 0.01 level of significance, the evidence is sufficient to conclude that the regional distribution of raw materials does not fit the distribution at the current excavation site. At the 0.01 level of significance, the evidence is insufficient to conclude that the regional distribution of raw materials does not fit the distribution at the current excavation site.

A market researcher believes that brand perception of one of the company's products may vary between different groups. After interviewing 401persons, the following data was compiled. Can we conclude that brand perception is dependent on age?

Step 1 of 8: State the null and alternative hypothesis.

Step 2 of 8: Find the expected value for the number of particpants who are 18-30 years old and have a favorable perception of the brand. Round your answer to one decimal place.

Step 3 of 8: Find the expected value for the number of particpants who are 30-45 years old and have a favorable perception of the brand. Round your answer to one decimal place.

Step 4 of 8: Find the value of the test statistic. Round your answer to three decimal places.

Step 5 of 8: Find the degrees of freedom associated with the test statistic for this problem.

Step 6 of 8: Find the critical value of the test at the 0.1 level of significance. Round your answer to three decimal places.

Step 7 of 8: Make the decision to reject or fail to reject the null hypothesis at the 0.1 level of significance.

Make the decision to reject or fail to reject the null hypothesis at the 0.05 level of significance.

Step 8 of 8: State the conclusion of the hypothesis test at the 0.1 level of significance.

  State the conclusion of the hypothesis test at the 0.05 level of significance.

There is significant evidence that brand perception and age are related.

or

There is not significant evidence that brand perception and age are related.

I have to answer these questions in a way that I can write out in a word document. Previous answer make little sense. I need to interpret (A) and I am just not understanding what the y intercept of -23 is indicating. I understand question b, not 100% on C please see below:  

A criminologist is interested in the effects of unemployment and policing on murder and has run the following multiple regression:

a. What is the Y-intercept? Interpret your results.

b. Which variables are significant at the 0.05 level?

c. What is the predicted homicide rate for a city with an unemployment rate of 5% and 250 police officers per 100,000 population?

Colleen is the marketing manager for Virtually Viral, an entertainment company that collects viral videos from around the Internet and aggregates them on their website. Whether it’s videos of cats or unusual marriage proposals, Virtually Viral collects them all. Almost all of Virtually Viral’s revenue comes from clicks on advertisements surrounding the videos. To maximize profits, Colleen tries to match ad content to video content. For example, for the ‘Wacky Weddings’ section of the website, most advertisements link to wedding planners and invitation/paper product suppliers. As part of this effort, Colleen contracted a web design firm to put together a new look for the website, with the goal of improving the amount of time visitors spend on the website. They produced four different versions, each arranging the videos and advertisements differently. Colleen is unsure which of these designs would result in the greatest amount of time spent on the site. To solve this problem, Colleen designs an experiment. She sets up a system to randomly assign visitors to the website to experience one of the four designs, recording the number of seconds that they spend on the site. She wants to compare the groups with each other and see if the different designs result in different lengths of time viewing the website. Whichever results in the longest visits will become the new design for the site in general. She knows from Chapter 7 that she has a research question and that this calls for some type of hypothesis testing. In Chapter 9, she learned that treating groups differently and comparing them means that she has independent data. But the independent-samples t-test only compares two groups with each other and she has four. Should she run multiple independent-samples t-tests? Or is there a better way?

Also complete an ANOVA and post-hoc test.

You are the foreman of the Bar-S cattle ranch in Colorado. A neighboring ranch has calves for sale, and you are going to buy some calves to add to the Bar-S herd. How much should a healthy calf weigh? Let x be the age of the calf (in weeks), and let y be the weight of the calf (in kilograms). x 1 3 10 16 26 36 y 46 51 74 100 150 200 Complete parts (a) through (e), given Σx = 92, Σy = 621, Σx2 = 2338, Σy2 = 82,693, Σxy = 13,639, and r ≈ 0.996. (a) Draw a scatter diagram displaying the data. (b) Verify the given sums Σx, Σy, Σx2, Σy2, Σxy, and the value of the sample correlation coefficient r. (Round your value for r to three decimal places.) Σx = Σy = Σx2 = Σy2 = Σxy = r = (c) Find x, and y. Then find the equation of the least-squares line y hat = a + bx. (Round your answers for x and y to two decimal places. Round your answers for a and b to three decimal places.) x = y = y hat = + x (d) Graph the least-squares line. Be sure to plot the point (x, y) as a point on the line. WebAssign Plot WebAssign Plot WebAssign Plot WebAssign Plot (e) Find the value of the coefficient of determination r2. What percentage of the variation in y can be explained by the corresponding variation in x and the least-squares line? What percentage is unexplained? (Round your answer for r2 to three decimal places. Round your answers for the percentages to one decimal place.) r2 = explained % unexplained % (f) The calves you want to buy are 12 weeks old. What does the least-squares line predict for a healthy weight? (Round your answer to two decimal places.) kg

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. x 3.4 4.0 3.3 4.5 2.6 3.2 3.4 y 5.5 10.0 11.2 10.0 7.9 3.9 5.5 (a) Make a scatter diagram of the data. Then visualize the line you think best fits the data. (b) Use a calculator to verify that Σx = 24.4, Σx2 = 87.26, Σy = 54.0, Σy2 = 463.56 and Σxy = 192.38. Compute r. (Round to 3 decimal places.) As x increases, does the value of r imply that y should tend to increase or decrease? Explain your answer. Given our value of r, we can not draw any conclusions for the behavior of y as x increases. Given our value of r, y should tend to decrease as x increases. Given our value of r, y should tend to increase as x increases. Given our value of r, y should tend to remain constant as x increases.

A survey of 23 grocery stores revealed that the average price of a gallon of milk was $3.11 with a standard error of $0.30. What is the 95% confidence interval to estimate the true cost of a gallon of milk?