23. Which of the following statements about the correlation coefficient is/ are true? I) The correlation coefficient and the slope of the regression must have the same sign. i.e It is not possible to have one of them positive and the other negative. II) A correlation of 1.0 indicates a perfect cause-and-effect relationship between the variables. III) Correlations of +0.9 and -0.9 indicate the same degree of clustering around the regression line. a) Only statement I is true Only statement II is true Only statement III is true Only statements I and III are true All three statements (i.e. I, II and III) are true indicates the strongest linear relationship28. A researcher wants to investigate whether different forms of exercise can be used to help hyperactive children. A group of 90 children is divided into two groups according to age - those aged 9-12 and those aged 5-9. Within each age group the children are randomly assigned to one of three groups. The first group will just do their normal exercise. The second group will be given an additional exercise routine (moderate). The third group will be given an additional exercise routine (strenuous). At the end of a four month period parents will be asked to evaluate their children's progress. Is this a completely randomized design or a randomized block design? Describe Design of Experiment. Completely randomized over one factor (exercise). Randomized block design, blocking on age, with one factor, exercise. Randomized block design, blocking on exercise, with one factor, age. Completely randomized over two factors, exercise and age. None of the above.20. The Test of English as a Foreign Language Skills (TOEFL) scores are approximately normally distributed with a mean of 540 and standard deviation of 60. A person received a score that was in the 80th percentile of everyone who took the exam (This means 80% of the scores are below this person's score). This person's score must be: 540 590 N 552 620 580 Co 4 8 - 540 = 4831. The correlation(r) between two quantitative variables z and y is zero. Based on this information we can conclude that: (a) we have done something wrong in our calculation of r. (b) there is no association between the two variables. (c) there is a non-linear association between the two variables. (d) we can increase the correlation by applying an appropriate linear transformation on x or y. (e) there is no linear association between r and y. 32. Table below shows the association between 1500 respondents' food insecurity and their highest level of education. Each cell in the table displays two values. The first value is a cell count and the second value is a kind of percentage. Contingency table results: Rows: Highest Education Columns: Food Insecurity Food Secured |Moderate Food Insecure |Severe Food Insecure Total Some High School 218 15 241 90.46%) 6.22%) (3.32%) (100%) High School Diploma 268 18 293 (91.47%) (6.14%) (2.39%) (100%) Some Post-Secondary 64 11 5 80 (80% (13.75%) (6.25%) (100%) Post-Secondary 828 41 17 886 (93.45%) (4.63%) (1.92%) (100%) Total 1378 85 37 1500 (91.87%) 5.67% (2.47%) (100%) What kind of percentages (e.g., row, column, total) are displayed in each cell? (a) Row percentages id to notindictaib add editesb of thaw mai (b) Column percentages ofdaruse a to oget dedW Jediquod mistaso a (c) Joint percentages (d) Total percentages (e) We cannot determine the percentages based on the given information (5) 20