Multiple Choice

QUESTION 18 An ice cream shop nds that the correlation between daily high temperature and daily sales is 0.74. The interpretation of this value is as follows: The value of sales falls approximately $0.74 for each degree that the temperature increases. The slope of the linear relationship between temperature and sales is 4174-; there is a positive relation between the two. There is a positive association between temperature and sales: as the temperature falls, sales tend to decrease. There is a negative association between temperature and sales: as the temperature falls, sales tend to increase. There is a negative association between temperature and sales: as the temperature falls, sales tend to decrease by $0.74. QUESTION 19 Studies have shown that the number of fire engines at a re and the amount of damage done by the fire are highly and positively correlated. Which of the following conclusions seems most appropriate? send as few flre engines to a re as possible. the number of re engines and the amount of re damage are both related to a third factorthe size ofthe fireand so are correlated to one another the presence of more fire engines tends to cause more confusion, leading to greater re damage. res and fire engines have something in common they are both red. none of the above QUESTION 20 Which of the following best describes the coefcient of variation? it measures variation as a percentage of the mean. it calculated as the mean divided by the standard deviation. it is not helpful when comparing the dispersion in data sets that have different means it can only be calculate using population parameters, not sample statistics all of the above