2. A statistic professor wants to investigate that there is a difference between a man's height and a woman's height at SMC. She gathered 23 female statistics students in her class and found their mean height is 64.217 inches and their standard deviation is 2.2755 inches. On the other hand, there were 12 male statistics students who were asked their height; their mean height is 67.833 inches and the standard deviation is 3.738 inches.  

Construct a 95% confidence interval estimate for the difference between the corresponding population mean height of gender at SMC. (10 points)

• Find the point estimate (the difference between sample means)
• Determine critical value
• Find the margin of error
• Construct a confidence interval
• Does it appear that there is a difference in their height between men and women?

Market equilibrium occurs when the amount of people that are willing to buy equals the amount of people that are willing to sell. A steadfast tenant in economics. As students here at Post let’s surmise that right now Post is at market equilibrium. We have enough Instructors to match the number of students. However, two scenarios occur; first, student enrollment falls, so Post decides it must now raise tuition. Not good…. Or, enrollment increases! And Post decides to, you guessed it, increase tuition. Why in each scenario would the University raise tuition and, why should tuition NOT be raised, in either scenario? Talk to this from both your point of view as well as if you were on the Board of Directors for the University. What’s the right thing to do, and why???

A statistics student who is curious about the relationship between the amount of time students spend on social networking sites and their performance at school decides to conduct a survey. Three research strategies for collecting data are described below. Match each strategy with the correct sampling method. He randomly samples 40 students from the study's population, gives them the survey, asks them to fill it out and bring it back the next day. Answer 1 He gives out the survey only to his friends, and makes sure each one of them fills out the survey. Answer 2 He posts a link to an online survey on his Facebook wall and asks his friends to fill out the survey. Answer 3

Use the following set of Data Management final examination scores to answer the questions below:

92, 48, 83, 62, 76, 64, 81, 98, 70, 70, 55, 83, 46, 79, 70, 97, 91, 53, 86, 89

a. Determine the mean, median, mode, range, and standard deviation.

b. Find Q1 and Q3 and state the IQR. Determine if there are any outliers.

c. Construct a box and whisker plot (by hand or using technology).

d. Construct a histogram. Describe the shape of the distribution.

e. Students with scores above the 80th percentile will receive an Honours Award in Data Management. How many students will receive the award?

f. What percentile is someone at if they received a score of 70?

The “Online” group has developed a series of webinars for student focussing on ‘How to be motivated in the online environment’. Their package delivers 12 x 1 hour per week motivational webinars targeted to students around the world due to the Covid-19 pandemic and the fact that many courses have moved to virtual classrooms. “Online” has asked you to research customer preferences and to recommend a pricing policy. There are limited price differences relating to the timing of webinars in the Northern Hemisphere, however for Southern Hemisphere webinars running a class at or below 45 students (normal class size is 50) costs significantly more for “Online” to run.

c. Is the need to consider customer preferences different for this organisation than for another type of organisation? Why or why not?

The Schiffert Health Center at Virginia Tech wants to see whether putting antibacterial soap in the dormitory bathrooms will reduce the number of visits to the infirmary. VT has 47 on-campus residence halls. They are home for 9300 students. Twenty residence halls have been randomly selected. In all 2,000 students spanning over all selected halls. Half of the dormitories are chosen at random and supplied with the special soap; the remaining ones were supplied with regular soap. At the end of the semester, the two types of soap are compared using the number of visits to the infirmary per person per semester.

1. We have studied two types of designs (complete randomized design and complete randomized block design). According to this scenario above, what type is this design?

20. Some researchers claim that herbal supplements such as ginseng or ginkgo biloba enhance human memory. To test this claim, a researcher selects a sample of n = 28 college students. Each student is given a ginkgo biloba supplement daily for 6 weeks and then all of the participants are given a standardized memory test. Scores on the standardized test are μ = 80 and standard deviation of 15. The sample of 28 students had a mean score of M = 85. (8 points)
    1. Do the data indicate a significant effect of the herb on memory? Use a two-tailed test with α = 0.05. (Show all steps.)
    2. Compute Cohen's d to measure the size of the effect IF it exists.
    3. Write a sentence describing the outcome of the hypothesis test as it would appear in a research report.

At a certain university, 40% of the students come from Orange County, 20% come from Los Angeles County, 20% come from another county in California, 10% come from another state, and 10% come from a different country. Zoe wants to see if the students in her class fit or do not fit this profile. She takes a sample: 100 come from Orange County, 35 come from Los Angeles County, 30 come from another county in California, 20 come from another state, and 15 come from another country. Please calculate the test statistic, state the critical value, and come to a conclusion concerning the make-up of the class. Let α = .05.

Question 9 (1 point)
Twelve students who were not satisfied with their ACT scores particiapted in an online 10-hour training program. The ACT scores before and after the training for the 12 students are given below:

Student Before After
1 23 27
2 25 26
3 27 31
4 30 32
5 24 26
6 25 24
7 27 31
8 26 28
9 28 30
10 22 25
11 20 24
12 29 32
Test a claim that the program is effective in improving a student’ ACT score.

What is the p-value?

Question 9 options:

Essentially 0

0.0325

0.0478

1.000

A social scientist measures the number of minutes (per day) that a small hypothetical population of college students spends online.A social scientist measures the number of minutes (per day) that a small hypothetical population of college students spends online.

(a) What is the range of data in this population?
min

(b) What is the IQR of data in this population?
min

(c) What is the SIQR of data in this population?
min

(d) What is the population variance?


(e) What is the population standard deviation? (Round your answer to two decimal places.)
min