The following data represents the monthly phone use, in minutes, of a customer enrolled in a fraud prevention program for the past 20 months.

Question

The phone company decides to use the upper fence as the cut off Point for the number of minutes at which the customer should be contacted. What is the cutoff point. round to the nearest minutes.

424 307 413 371

467 341 335 521

510 375 512 336

521 489 465 380

515 440 395 450

Answer 1

Upper fence = Q3 + 1.5 X IQR

Put data into TI-84 (list 1)

STAT CALC 1

Make sure L1 is entered

Freqlist should be empty

Hit calculate

Q1 = 373

Q3 = 499.5

IQR = Q3 - Q1 = 126.5

Upper fence = 499.5 + 1.5 x 126.5 = 689.25, = 689 to nearest minute