assigned, the investigator asked 'May I use the machine ?'(let's call this group the 'request-only' group). In that case, 18 out of 30 people allowed the investigator to go first. In the other group of 30 people, the investigator asked 'May I use the machine because I have to make copies?' (let's call it the 'bad reason' group). In that case, 28 out of 30 people allowed the investigator to go first. You can enter the data yourself, or you may enter the data (called `d`) by copying and pasting the code below (in blue). Note that several questions will be associated to these data. #-------------------------------------------------------------- # Code to enter data 'd' d = rbind(c(28,2), c(18,12)); colnames(d) = c('Yes', 'No'); rownames(d) = c('Bad reason','Request only'); d = t(d); d #-------------------------------------------------------------- The data should look like that: Bad reason Request only
Sixty people who were about to use a photocopy machine were approached by an investigator. In 30 cases randomly assigned, the investigator asked 'May I use the machine ?'(let's call this group the 'request-only' group). In that case, 18 out of 30 people allowed the investigator to go first. In the other group of 30 people, the investigator asked 'May I use the machine because I have to make copies?' (let's call it the 'bad reason' group). In that case, 28 out of 30 people allowed the investigator to go first.
You can enter the data yourself, or you may enter the data (called `d`) by copying and pasting the code below (in blue). Note that several questions will be associated to these data.
#--------------------------------------------------------------
# Code to enter data 'd'
d = rbind(c(28,2), c(18,12)); colnames(d) = c('Yes', 'No');
rownames(d) = c('Bad reason','Request only'); d = t(d); d
#--------------------------------------------------------------
The data should look like that:
Bad reason Request only
Yes 28 18
No 2 12
What kind of table is it?
Flag question: Question 2
Show the data `d` using a mosaic plot (don't forget the rules for a good graph and to include your R code or EXCEL file!).
Flag question: Question 3
Show the data `d` using a grouped bar graph (don't forget the rules for a good graph and to include your R code or EXCEL file!).
Flag question: Question 4
What are the expected frequencies under the null hypothesis that the `bad-reason` approach is neither better nor worse than the request-only approach. Do not forget to include your R code or calculations!
Flag question: Question 5
You decide to use a Chi-square test to test the null hypothesis that the `bad-reason` approach is neither better nor worse than the request-only approach. Are the assumptions of such a test verified? Explain.
Flag question: Question 6
Run the Chi-square test, report the results, and conclude. Do not forget your R code or to include your calculations (if you use EXCEL, I further recommend sending me the EXCEL file at the end via email)!
Flag question: Question 7
The chi-square test is not exact. Do you know an alternative exact test for these kind of data? Name this exact test (5 Pts), and then run it and conclude (up to 5 Bonus Pts).
Flag question: Question 8
Problem # 2 -
One-hundred and fifty plants are assigned to one of four possible phenotypes (A, B, C or D). We observe 85 plants of type A, 35 of type B, 28 of type C, and 2 of type D.
You want to test the null hypothesis that the phenotypic ratio in the population is 9:3:3:1 (i.e., out of 16 plants, 9 are of type A , 3 are of type B , 3 are of type C, and 1 is of type D).
What are the expected frequencies under the null hypothesis (i.e., how many plants of each phenotype do you expect to get out of 150)? Remember to include your R code or calculations!
Flag question: Question 9
Problem # 2 -
What kind of chi-square test is relevant here to test the null hypothesis? Are the assumptions of the test verified?
question 10
Problem # 2 -
Test the null hypothesis that the phenotypic ratio is 9:3:3:1. Do not forget your R code or to include your calculations (if you use EXCEL, I further recommend sending me the EXCEL file at the end via email)! Remember to make a proper conclusion, i.e. a complete sentence answering the question, including the P-value and its correct interpretation.
Hi! Thank you for the question, As per the honor code, we are allowed to answer first three subparts of one question at a time so we are answering the first three subparts of first question as you have not mentioned which one you are looking for. Please re-submit the question separately for the remaining question and subparts.
Given:
The data given is shown below
| Bad reason | Request only | |
| Yes | 28 | 18 |
| No | 2 | 12 |
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What are the expected frequencies under the null hypothesis that the `bad-reason` approach is neither better nor worse than the request-only approach. Do not forget to include your R code or calculations!
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