Partie B : VPP et maladie rare On dispose d'un test pour dépister une maladie rare. Le fabricant du test fournit les caractéris- tiques suivantes: - la probabilité qu'un individu malade ait un test positif est de 0,99 ; - la probabilité qu'un individu non malade ait un test négatif est de 0,99 . On envisage un dépistage systématique sur une population dans laquelle on estime à \( f \) (avec \( 0 \leqslant f \leqslant 1 \) ) la proportion de gens malades. 1. Expliquer pourquoi VPP \( =\frac{99 f}{98 f+1} \).

\#2 A survey was taken comparing the number of hours per week students spent studying and their performance on an exam. If a linear regression was performed and the correlation coefficient was -0.017 , what can be said about these results? a. As the number of hours spent studying increases, student exam performances will likely not change. b. As the number of hours spent studying inrceases, student exam performances will probably increase. c. As the number of hours spent studying increases, student exam performances will probably decrease. d. There is little evidence of a linear relationship between the number of hours spent studying and student exam performances.

In a class, there are 750 learners in 1st year, 420 learners in 2 nd year. Draw a pie graph to represent the numbers of learners in these groups.

16. Bob made a picture graph of the marbles he and his friends have. How many more marbles does Bob have than Kayla? Explain ho you found the answer.

For the given data: 22; \( 9 ; 19 ; 2 ; 38 ; 40 ; 7 ; 38 ; 44 ; 6 ; 12 ; 10 ; 20 ; 31 ; 48 ; 45 \) Determine the Quartiles, Q1, Q2 and Q3 of the data: Q1: Q2:

\#7 A set of data has correlation coefficient \( r \). For which value of \( r \) would the average magnitude of the residuals be the smallest? a. \( r=-0.034 \) b. \( r=0.472 \) c. \( r=0.908 \) d. \( r=0.952 \)