As part of a larger study, Bratanova et al. (2015)1 investigated whether a person's taste for biscuits could be influenced by the ethicality of the manufacturing company. A fictional biscuit company was used for the study. 112 undergraduate students from a Belgian university volunteered to participate in the study.

The students were randomly assigned to one of two groups: 53 to a group that were given a description that portrayed the company as environmentally friendly and the remaining 59 to another group that were given a description that portrayed the company as environmentally harmful.

Students in both groups were then given the same type of biscuit to taste and told that it was made by the company in the description. After tasting the biscuit, both groups of students were asked to rate on a 7-point scale how likely it was that they would buy biscuits from this company in the future (Future buy).

For the purpose of analysing this data we will treat Future buy as a numeric variable where 1 = not at all likely, and 7 = very likely.

Question 5. [ 12 marks] [Chapters 7 and 8] A lecturer obtained data on all the emails she had sent from 2017 to 2021, using her work email address. A random sample of 500 of these emails were used by the lecturer to explore her emailing sending habits. (a) For each of the scenarios 1 to 4 below: [4 marks 1 mark for each scenario] (i) Write down the name of the variable(s), given in the table above, needed to examine the question. (ii) For each variable in (i) write dovm its type (numeric or categorical). Some of the variables selected were: Year Subject length Word count Reply email Time of day Email type The year the email was sent: (b) What tool(s) should you use to begin to investigate the scenarios 1 to 4 below? Write down the _ 2 0 l 7 scenario number 1 to 4 followed by the appropriate tool. Hint: Refer to the blue notes in Chapter 1 2 0 1 8 in the lecture Workbook. [ 4 marks 1 mark for each scenario ] 2 0 l 9 (c) Given that the underlying assumptions are satised, which form of analysis below should be used 2 0 2 0 in the investigation of each of the scenarios 1 to 4 below? Write down the scenario number 1 to 4 2 O 2 1 followed by the appropriate Code A to F. [ 4 marks 1 mark for each scenario ] The number of words in the email subject The number of words in the body of the email Scenario 1 Whether the email was sent as a reply to another email: Yes Scenario 2 _ No Scenario 3 The time of day the email was sent: AM PM Scenario 4 The type of email sent: Text, only Not text only Is there a difference between the proportion of AM reply emails and the proportion of PM reply emails? Does the average word count of the emails depend on year? Is there a difference between the proportion of text only emails sent in 2017 compared to the proportion of text only emails sent in 2021'? Is the number of words in the email's subject related to its type? Code Form of analysis A B C D E F One sample t-test on a mean One sample t-test on a proportion One sample t-test on a mean of differences Two sample t-test on a difference between two means t-test on a difference between two proportions One-way analysis of variance F -test