Question

money enough to build one facility, the president wants to ask students which one they feel is in greater need of renovation. Suppose there are 500 male students and 400 female students in the school. a) What is the population under study? (2 points) b) The president wants to randomly ask 50% of the students. How many students would this be? (2 points) c) Now the president wants to keep the correct proportion of female to male students in the sample. What type of sampling method would be used here? How many girls would be selected? (4 points) d) What is the level of measurement for the students' response? (2 points) 2. The following are two hypothetical statements by American politicians. Politician A: "Our economy is in the crapper! Thirty states had falling incomes last year." Politician B: “Our economy is showing appreciable gains: Seventy percent of Americans had rising incomes last year." a) Suppose both statements are true. How to reconcile these two seemingly contradicting statements? (4 points) b) What lessons can we learn about descriptive statistics from this example? (4 points) 3. On a Saturday evening your father and mother take you out for dinner. There are 7 other customers in the restaurant. Their ages are as following: 44, 56, 25, 40, 32, 34, 38. a) Write down the ages for your father, mother and you. (2 points) b) Construct a stem-and-leaf graph for the age of all the customers in the restaurant. (3 points) c) Comment on the shape of the whole data set. (3 points) d) Compute the mean, the median and the mode of the whole data set. (6 points) e) Compute the 40 percentile of the whole data set. (3 points)

Answer 1

solution: 3 Given: 44 25 32 311 40 34 38 a) ages for father, mother and b) stem and leaf plot: you : A5, 4H, 2] data set 6 shape leaf stem stem leaf 2 UT -- per unhle f 2 median 2 8 3 dmth 0 4 4 5 t for 4 mode Olli d) - = 37.9 44+56 +25 +32 +40+ mean 34 +38+44+45+21 379 median: mid value _38+up 278 1o = 39 2 2 mode frequently occurring 44 Skewed right tailed fo) pybu 40 mean : 37.9 N median : 39 mode 44

e)

To find Hon percentile formule : (n+1) xpth value 100 here h =10 p=40 (1011) x 40 value 100 2 11 x 4.0 4.4 value H th value N 34 tota percentile = 34