Chapter 5, Problem 5.42CRP

If 10 percent of the parts made by a certain company are defective and have to be remade, what is the chance that a random sample of four parts has one that is defective?

Question 4 Fourteen individuals were given a complex puzzle to complete. The times in seconds was recorded for their first and second attempts and the results provided below: 1 2 3 first attempt 172 255 second attempt 70 4 5 114 248 218 194 270 267 66 6 7 230 219 341 174 8 10 9 210 261 347 218 200 281 199 308 268 243 236 300 11 12 13 14 140 302 a. Calculate a 95% confidence interval for the mean time taken by each individual to complete the (i) first attempt and (ii) second attempt. [la] b. Test the hypothesis that the difference between the two mean times for both is 100 seconds. Use the 5% level of significance. c. Subsequently, it was learnt that the times for the second attempt were incorrecly recorded and that each of the values is 50 seconds too large. What, if any, difference does this make to the results of the test done in part (b)? Show all steps for the hypothesis test

Question 3 3200 students were asked about the importance of study groups in successfully completing their courses. They were asked to provide their current majors as well as their opinion. The results are given below: Major Opinion Psychology Sociology Economics Statistics Accounting Total Agree 144 183 201 271 251 1050 Disagree 230 233 254 227 218 1162 Impartial 201 181 196 234 176 988 Total 575 597 651 732 645 3200 a. State both the null and alternative hypotheses. b. Provide the decision rule for making this decision. Use an alpha level of 5%. c. Show all of the work necessary to calculate the appropriate statistic. | d. What conclusion are you allowed to draw? c. Would your conclusion change at the 10% level of significance? f. Confirm test results in part (c) using JASP. Note: All JASP input files and output tables should be provided

Question 1 A tech company has acknowledged the importance of having records of all meetings conducted. The meetings are very fast paced and requires equipment that is able to capture the information in the shortest possible time. There are two options, using a typewriter or a word processor. Fifteen administrative assistants are selected and the amount of typing time in hours was recorded. The results are given below: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 typewriter 8.0 6.5 5.0 6.7 7.8 8.5 7.2 5.7 9.2 5.7 6.5 word processor 7.2 5.7 8.3 7.5 9.2 7.2 6.5 7.0 6.9 34 7.0 6.9 8.8 6.7 8.8 9.4 8.6 5.5 7.2 8.4 a. Test the hypothesis that the mean typing time in hours for typewriters is less than 7.0. Use the 1% level of significance. b. Construct a 90% confidence interval for the difference in mean typing time in hours, where a difference is equal to the typing time in hours of word processors minus typing time in hours of typewriter. c. Using the 5% significance level, determine whether there is…

Illustrate 2/7×4/5 using a rectangular region. Explain your work. 

Write three other different proportions equivalent to the following using the same values as in the given proportion 3 foot over 1 yard equals X feet over 5 yards

2. An experiment is set up to test the effectiveness of a new drug for balancing people's mood. The table below contains the results of the patients before and after taking the drug. The possible scores are the integers from 0 to 10, where 0 indicates a depressed mood and 10 indicates and elated mood. Patient Before After 1 4 4 2 3 3 3 6 4 4 1 2 5 6 5 6 1 3 7 4 7 8 6 9 1 4 10 5 4 Assuming the differences of the observations to be symmetric, but not normally distributed, investigate the effectiveness of the drug at the 5% significance level. [4 Marks]

3. (i) Consider the following R code: wilcox.test(UK Supermarkets $Salary ~ UKSupermarkets $Supermarket) (a) Which test is being used in this code? (b) What is the name of the dataset under consideration? How would be adapt this code if we had ties? What other command can be used which deals with ties? (ii) Consider the following R code: install packages("nortest") library(nortest) lillie.test (Differences) (a) Assuming the appropriate dataset has been imported and attached, what is wrong with this code? (b) If this code were to be corrected, what would be determined by run- ning it? [3 Marks]

1. (i) Explain the difference in application between the Mann-Whitney U test and the Wilcoxon Signed-Rank test, i.e. in which scenarios would each test be used? (ii) What is the main procedure underlying these nonparametric tests? [3 Marks]