Right versus left. The design of controls and instruments affects how easily people can use them. Timothy Sturm investigated this effect in a course project, asking 25 right-handed students to turn a knob (with their right hands) that moved an indicator by screw action. There were two identical instruments: one with a right-hand thread (the knob turns clockwise), and the other with a left-hand thread (the knob turns counterclockwise). Table 20.4 gives the times in seconds each subject took to move the indicator a fixed distance.33 DATA RTLFT

(a) Each of the 25 students used both instruments. Explain briefly how you would use randomization in arranging the experiment.

The price of a certain combo meal at different franchises of a national fast food company varies from​ $5.00 to ​$17.37and has a known standard deviation of

$2.09. A sample of 29students in an online course that includes students across the country stated that their average price is $6.00.

The students have also stated that they are generally unwilling to pay more than $6.75 for this meal. Formulate and conduct a hypothesis test to determine if you can conclude that the population mean is less than $6.75.

Use a level of significance of 0.05.

Is there sufficient evidence at the 0.05 level of significance that the population mean is less than ​$6.75​?

Determine the null​ hypothesis, H0​,and the alternative​ hypothesis, H1.

compute test statistic

find the pvalue

state the conclusion

Tracy is in her last semester of nursing school where she is taking a course in which her class learns about the importance of evidence-based practice. Dr. Minturn, the nursing professor who teaches the course, has asked the students to write a paper about a mock research study of their choosing. The students are to pose a clinical question and then map how they would create a research study around the question. They are not to actually carry out the research, but they are to envision what their study would look like and then map it on paper.

1. Tracy needs to conduct a literature review of her chosen phenomena of study. One database she can use to obtain peer reviewed nursing articles is:

In an experiment to determine the effect of nutrition on the attention spans of elementary school students, a group of 45 students is divided into three groups of 15, and randomly assigned to each of three meal plans: no breakfast, light breakfast, and full breakfast. Their attention spans, in minutes, were recorded. Say you want to test the hypothesis that the means of the attention spans are not all the same at a level of significance of 5%.

(a) (3 pts) What are the null and alternative hypotheses?

(b) (4 pts) Suppose that you find MSG=26 and MSE=3.1. Find the F-statistic, and estimate the p-value of your data using the F-table.

(c) (3 pts) Should you accept or reject? Explain.

Suppose the incidence rate of influenza (flu) during the winter of 1998-1999 (i.e. from December 21, 1998 to March 20, 1999) was 50 events per 1000 person-months among students in high schools in a particular city. Among 1200 students in one high school in the city, 200 developed a new case of influenza over the winter of 1999-2000 (i.e. the 90 days from December 21, 1999 to March 20, 2000).

Question: Test the hypothesis that the rate of flu has changed from winter 1998-1999 to winter 1999-2000. Write
out all 4 steps of the hypothesis test including a two-tailed p-value.

The time needed to complete a final examination in a particular college course is normally distributed with a mean of 83 minutes and a standard deviation of 13 minutes. Answer the following questions. Round the intermediate calculations for z value to 2 decimal places. Use Table 1 in Appendix B. What is the probability of completing the exam in one hour or less (to 4 decimals)? What is the probability that a student will complete the exam in more than 60 minutes but less than 75 minutes (to 4 decimals)? Assume that the class has 60 students and that the examination period is 90 minutes in length. How many students do you expect will be unable to complete the exam in the allotted time (to the next whole number)?

between-subjects t-test

A math teacher was interested in determining performance as a function of time of day during morning and evening classes. He recruited twenty students to participate: 10 were randomly assigned to participate in the morning class (8am), and the other 10 students were assigned to the afternoon class (3pm).

Data Set:

From past experience, Dr. R-P believes that the average score on a Research Methods Course is 75. A sample of 10 students exam scores is as follows:
80, 68, 72, 73, 76, 81, 71, 71, 65, 53.
Test the claim that the students average is still 75. Use α = 0.01. [You need to first compute the mean and the standard deviation, then the standard error from your sample. To do this, use the computational method for ungrouped data that we learned in chapter 5, page 128-129. (Show all your work; this gives you a complete view of where all these numbers we use in hypothesis testing or confidence interval come from)].

In a school district, all sixth grade students take the same standardized test. The superintendant of the school district takes a random sample of 22 scores from all of the students who took the test. She sees that the mean score is 160 with a standard deviation of 28.2396. The superintendant wants to know if the standard deviation has changed this year. Previously, the population standard deviation was 28. Is there evidence that the standard deviation of test scores has increased at the α=0.005 level? Assume the population is normally distributed. Step 2 of 5 : Determine the critical value(s) of the test statistic. If the test is two-tailed, separate the values with a comma. Round your answer to three decimal places.

Breathing rates for humans can be as low as 4 breaths per minute or as high as 70 or 75 for a person doing strenuous exercise. Suppose that the resting breathing rates for college-age students have a distribution that is mound-shaped, with a mean of 12 and a standard deviation of 2.3 breaths per minute. What fraction of all students have breathing rates in the following intervals.

a. 9.7 to 14.3 breaths per minute

b. 7.4 to 16.6 breaths per minute

c. More than 18.9 or less than 5.1 breaths per minute

Please explain how every number was solved/or found, please. I'm very confused about how this should be solved.