Let's say you want to poll a random sample of 150 students on campus to see if they prefer to take online classes. Of course, if you took an actual poll you would only get one number (your sample proportion, p-hat). But, imagine all the possible samples of 150 students that you could draw and the imagined histogram of all the sample proportions from those samples. 1. What shape would the histogram of all the possible sample proportions (p-hat's) have? 2. Where would the center of that histogram be? (This answer should be a description in words based on what we know about p-hat sampling distributions.) Now, given the information that about 35% of students actually prefer to take classes online respond to the following: 3. Discuss the conditions necessary to use the normal model here and explain whether or not they are met. 4. If you were to use the normal model for this p-hat sampling distribution, what would be the parameters (mean and standard deviation) for your model

Almost all medical schools in the United States require students to take the Medical College Admission Test (MCAT). To estimate the mean score ? of those who took the MCAT on your campus, you will obtain the scores of an SRS of students. The scores follow a Normal distribution, and from published information you know that the standard deviation is 10.8 . Suppose that, unknown to you, the mean score of those taking the MCAT on your campus is 495 . In answering the questions, use ? ‑scores rounded to two decimal places. (a) If you choose one student at random, what is the probability that the student's score is between 490 and 500 ? Use Table A, or software to calculate your answer. (Enter your answer rounded to four decimal places.) probability: (b) You sample 36 students. What is the standard deviation of the sampling distribution of their average score ?¯ ? (Enter your answer rounded to two decimal places.) standard deviation: (c) What is the probability that the mean score of your sample is between 490 and 500 ? (Enter your answer rounded to four decimal places.) probability:

Three independent random samples of community college students were obtained to find out how many hours the students spent each week doing math homework outside of the classroom. The samples were made up of students in pre-algebra, elementary algebra, and intermediate algebra.

a. How many comparisons would be required to compare the populations two at a time?

b. If we wanted an overall significance of .05 what significance would we use in each test according to the Bonferroni correction?

c. Assuming we meet the requirements, find the p-values for each of the possible two tailed tests. PreAlg and ElemAlg: p-value= PreAlg and InterAlg: p-value= ElemAlg and InterAlg: p-value= d. What is your conclusion?

Answer questions 16 – 17 based on the following. A statistics teacher wants to see if there is any difference in the abilities of students enrolled in statistics today and those enrolled five years ago. A sample of final examination scores from students enrolled today and from students enrolled five years ago was taken. You are given the following information:

16. The 95% confidence interval for the difference between the two population means (Today – Five Years Ago) is

a. -9.92 to -2.08

b. -3.08 to 3.92

c. -13.84 to -1.16

d. -24.77 to 12.23

e. 2.08 to 9.92

17. The statistics teacher wishes to test, using a two-tailed approach, the hypothesis of no difference between the population mean scores using a 5% level of significance. The p-value associated with this test is: When computing two-tailed p-values, remember to use the 2p approach!

a. 0.0013

b. 0.0026

c. 0.4987

d. 0.9987

Acc105

Chapter 11 - Cost Behavior ( discussion board):

Please provide your thoughts on this simple example of cost behavior and then add an example of your own.

What do you typically pay for a large pizza? (There is no right or wrong price - just pick a reasonable price)
What would be the cost per student if two students buy that pizza?
What if four students buy a large pizza?
What does this illustrate about why average fixed costs change on a per-unit basis?

Let's add the fact that a beverage costs $1 and each student eating the pizza has one beverage. So, if two people were eating the pizza, the total beverage bill would come to $2; if four people, $4. The cost per beverage remains the same, but the total cost depends on the number of people ordering a beverage.
What does this tell us about how total variable costs vary per units (or in this case students)?

Please provide another basic example of cost behavior (related to fixed or variable).

Almost all medical schools in the United States require students to take the Medical College Admission Test (MCAT). To estimate the mean score ?μ of those who took the MCAT on your campus, you will obtain the scores of an SRS of students. The scores follow a Normal distribution, and from published information you know that the standard deviation is 10.810.8 . Suppose that, unknown to you, the mean score of those taking the MCAT on your campus is 495495 .

In answering the questions, use ?z‑scores rounded to two decimal places.

(a) If you choose one student at random, what is the probability that the student's score is between 490490 and 500500 ? Use Table A, or software to calculate your answer.

(Enter your answer rounded to four decimal places.)

probability:

(b) You sample 3636 students. What is the standard deviation of the sampling distribution of their average score ?¯x¯ ? (Enter your answer rounded to two decimal places.)

standard deviation:

(c) What is the probability that the mean score of your sample is between 490490 and 500500 ? (Enter your answer rounded to four decimal places.)

probability:

The Survey of Study Habits and Attitudes (SSHA) is a psychological test that measures the motivation, attitude toward school, and study habits of students. Scores range from 0 to 200. A selective private college gives the SSHA to an SRS of both male and female first-year students. The data for the women are as follows: 154 109 137 115 152 140 154 178 101 103 126 126 137 165 165 129 200 148 Here are the scores of the men: 108 140 114 91 180 115 126 92 169 146 109 132 75 88 113 151 70 115 187 104

Most studies have found that the mean SSHA score for men is lower than the mean score in a comparable group of women. Is this true for first-year students at this college? Use a 1% significance level.

(a) Hypotheses and results:

(b) Draw a picture and label p-value and horizontal axis:

(c) Draw a conclusion. Don’t just accept or reject. Say what it means in terms of this problem.

1. You wish to see if a difference exists in the average SAT score for students at two local colleges. A random sample of 200 students from College A had an average SAT score of 1641.7 with a standard deviation of 28.4. A random sample of 178 students from College B had an average SAT score of 1629.8 with a standard deviation of 25.6. Does this show, at 95% confidence, a difference in the average SAT scores? Be sure to state the interval.

   		I am 95% confident that the difference in average SAT scores for the two colleges is between 5.8773 and 11.5287. We failed to show a difference.
   		I am 95% confident that the difference in average SAT scores for the two collegesis between 5.8773 and 11.5287. The evidence suggests the averages are different.
   		I am 95% confident that the difference in average SAT scores for the two collegesis between 6.4386 and 17.361. We failed to show a difference.
   		I am 95% confident that the difference in average SAT scores for the two collegesis between 6.4386 and 17.361. The evidence suggests the averages are different.

A hypothetical data shows that, in a year, of all the adult population, 20,500,000 were employed, 755,000 were unemployed, 45,000 were workers with part-time jobs looking for full-time jobs, 25,000 were discouraged workers and 8,500,000 were not in the labor force.

1. Use the above information and calculate the labor force participation rate and the unemployment rate.
2. Suppose that the natural rate of unemployment is 1.5 percent and the potential GDP is RM 850 billion, how much would be the actual GDP achieved in the above case?
3. Suppose that 2,500,000 students graduated from higher education institutions and begin to look for jobs. Ceteris paribus, determine the new unemployment rate if none of the students have found jobs yet. How this will change your answer in (b)?
4. Now suppose that 1,500,000 of the students whom graduated in (c) find jobs and the remaining are not yet employed. Ceteris paribus, determine the new unemployment rate. Clearly show your working for all calculations.
5. Simulate a scenario in which both employment and unemployment could both possibly increase.

Almost all medical schools in the United States require students to take the Medical College Admission Test (MCAT). To estimate the mean score ?μ of those who took the MCAT on your campus, you will obtain the scores of an SRS of students. The scores follow a Normal distribution, and from published information you know that the standard deviation is 10.810.8 . Suppose that, unknown to you, the mean score of those taking the MCAT on your campus is 495495 .

In answering the questions, use ?z‑scores rounded to two decimal places.

(a) If you choose one student at random, what is the probability that the student's score is between 490490 and 500500 ? Use Table A, or software to calculate your answer.

(Enter your answer rounded to four decimal places.)

probability:

(b) You sample 3636 students. What is the standard deviation of the sampling distribution of their average score ?¯x¯ ? (Enter your answer rounded to two decimal places.)

standard deviation:

(c) What is the probability that the mean score of your sample is between 490490 and 500500 ? (Enter your answer rounded to four decimal places.)

probability: