Question

The following data give the speeds (in miles per hour) of 12 cars traveling on a highway. 67 71 57 54 69 74 77 62 61 59 58 63 a. Calculate the values of three quartiles. (3 points) b. Find the (approximate) value of the 40th percentile. (2 points) c. Find the percentile rank of 62: (3 points)

Answer 1

Date solution- Heee, n=12 we obrange the dato by ascending oedee 54, 57, 58, 59, 61, 62, 63,67,69,71,74,77 1 a vawes of theee quaelles th obseevation gi= (n+1) = (3.25) th Observation =zed obs +0.25(4th Obs - 360 obs) = 58 +0.255( 59 - 58) :.8, = 58.25 02-(2007))* th obseerattor - 6.5 th obseevation =6th obs +0.50 thobs - 6th obs) =62+0.5(63-62) :.92=62.5 8(n+th observation 4 = 19.95)th observattom gth obsto.75( 10th obs-gth obs) = 69 +0.75 (71 - 69) = 70.5
a) Q1= 58.25 ; Q2= 62.5 ; Q3= 70.5

b) value of 40th percentile is 5.2

c) percentile rank of 62 is 46