Software:
You must use Minitab to produce any graphs, tables and descriptive statis- tics.
Statistics:
Must be relevant: you will be penalised for including statistics which are not relevant to the questions asked.
Comments:
• must be in the context of the data.
• should be supported by relevant statistics where possible.
• should be concise and informative. Word limits, where given, must be strictly adhered to (all word limits are a maximum, you will be penalised for going over this limit!). You may use dot-points.
Question 1: Is there a difference in immune response between two delivery methods for monkeypox vaccine?
This question is based on simulated data for the study by Sharon E. Frey et al. (2015) ‘Comparison of lyophilized versus liquid modified vaccinia Ankara (MVA) formulations and subcutaneous versus intradermal routes of immu- nisation in healthy vaccinia-na ̈ıve subjects’, Vaccine, Volume 33 Issue 39, 5225–5234. You can find this article at: https://www.sciencedirect.com/science/article/pii/S0264410X15008762, also linked on the LMS.
You DO NOT need information from this article to answer the questions; it is provided for interest only.
Monkeypox is a severe illness caused by a virus. Due to its similarity with other pox-family viruses, the current strain circulating in non-endemic regions (Monkeypox Clade IIb) is known to be prevented by the modified vaccinia Ankara (MVA) vaccine, originally developed for smallpox.
This study, in part, examined two treatments:
Subcutaneous (SC) group a full dose of the MVA vaccine is injected into the tissue layer between the skin and the muscle.
Intradermal (ID) group a one-fifth dose of the MVA vaccine is injected just below the surface of the skin (between the epidermis and the hypodermis).
We are only interested in the relative effectiveness of these two treat- ments. The response variable measured is a measure of the vaccine effec-tiveness, L2NT.
The data is available as Asst2 2022 data.csv on the LMS Assignment
2 page.
(a). Explain why subcutaneous injection was chosen as the second treat- ment, rather than a placebo.
(b). Produce an appropriate graph showing vaccine effectiveness for both groups.
(c). Comment on the effect of vaccination method on L2NT. You should support your comments with relevant statistics, but do not include Minitab output.
Your comments must be less than 150 words.
(d). Calculate a 95% Confidence Interval for the difference in mean L2NT for the two groups. Show all of your calculations (do not include Minitab output, but you may use Minitab to obtain summary statistics and relevant distribution values).
(e). What assumptions have you made in calculating this interval? Were they satisfied? (You need to provide evidence, in the form of one graph and a calculation.)
(f). Without doing further calculation, would a test of the hypotheses
H0 :μ1−μ2 =0andH1 :μ1−μ2 ̸=0besignificantattheα=0.05 level? Explain briefly.
Question 2: Political Polling
This question is inspired by the report ‘Guardian Essential poll: Daniel An- drews in strong position for Labor victory in Victorian election’, Benita Ko- volos (2022)The Guardian Australia (https://www.theguardian.com/australia- news/2022/sep/11/guardian-essential-poll-daniel-andrews-in-strong-position- for-labor-victory-in-victorian-election), also linked on the LMS.
You DO NOT need information from this article to answer the questions; it is provided for context only.
This report discusses the results from a poll of 536 people, where they were asked about their voting intentions for the upcoming Victorian state election in November 2022. The poll identified 189 people who were intend- ing to give their first preference to the Australian Labor Party (ALP, the current government) in the next election.
(a). Outline how you would collect a representative sample of a similar size to this poll. Your answer will be assessed both on the statistical validity and the practicality of your design.
(b). Construct a 95% confidence interval for the proportion of Victorians who intend to give their first preference to the ALP.
(c). There were several undecided voters, with only 472 expressing an ab- solute preference. Conduct an approximate Hypothesis Test (using α = 0.05) to determine if there is a difference between decided vot- ers in this poll, and the result of the previous election (where the ALP received 43% of first preference votes). Show all of your calcula- tions and steps.
Your answer needs to (the 5 step process meets these requirements):
• State the hypotheses in terms of the parameter(s) of interest.
• Calculate sd(estimator).
• Calculate the test statistic, and give its distribution under the
null hypothesis.
• Give the P -value for the test, using Minitab (you should not use Minitab for other parts of this question).
• State your conclusion in the context of the data.
(d). An employee of the polling company is looking at the data on a seat- by-seat basis. They find that in the seat of Ripon in Western Victoria only 1 out of 7 respondents were planning on putting Labor as their first preference. Would you advise them to use the same method as used in part (c) to test if support for the ALP has changed? Why/why not?
(e). It is believed that the true proportion of first-preference votes for the ALP at the next election will be no more than 45%. Researchers would like to estimate this proportion using an 80% confidence interval based on a normal approximation, with a maximum margin of error of 0.04. What sample size would be required to achieve this? Show your calculations as well as your answer.
Question 3: Interpreting Research
This question requires you to interpret the following small section of the article: Kathleen Gee, Mara Gonzalez and Carrie Cooper (2020) ‘Outcomes of inclusive versus separate placements: A matched pairs comparison study’, Research and Practice for Persons with Severe Disabilities, 45 (4) 223–240. You can obtain this article from the Library website (online Journal search). You DO NOT need information from this article to answer the questions; it is provided for context only.
The students in inclusive classrooms were found to have a signif- icant, large effect size as compared with the students in separate classrooms for the following variables: being involved in an ac- tivity that typical peers might be involved in at school (.58, p < .001), being with typical peers (.62, p < .001), being socially en- gaged (.58, p < .001), and being engaged in peer-to-peer learning (.52, p = .002).
(a). For one of the four hypothesis tests in the quote, clearly state the null and alternative hypotheses being tested. You may need to define appropriate parameter(s); and you may assume that effect size is a constant multiplied by the mean.
(b). The title of the study mentions it is a “matched pairs” comparison study. Explain what this means in terms of this particular study. Note: you do not need any additional information other than what is given in this question.
Relevance, Formatting & Submission
You can gain an additional 2 marks by:
• only including relevant material;
• submitting a clearly legible assignment (eg all pages correct orienta- tion);
• selecting correct page(s) for each part of each question (when you upload your assignment to Gradescope, it will ask you to select pages: you can select multiple pages for a question part, you can also select the same page for multiple parts).
