Question

The time (in months) to the first electrical malfunction of a pacemaker was recorded for a sample of 89 heart patients:

24 20 16 32 14 22 2 12 24 6 10 20 8 16 12 24 14 20 18 14 16 18 20 22 24 26 28 18 14 10 12 24 6 12 18 16 34 18 20 22 24 26 18 2 18 12 12 8 24 10 14 16 22 24 22 20 24 28 20 22 26 20 6 14 16 18 24 18 16 6 16 10 14 18 24 22 28 24 30 34 26 24 22 28 30 22 24 22 32

(a) Construct a relative frequency distribution for this data using the following class intervals 0 - < 6, 6 - < 12, and so on. (b) Draw the corresponding histogram and describe its shape. (c) If the pacemaker must be replaced as soon as the first electrical malfunction occurs, approximately what proportion require re- placement within less than 2 years of implantation? (d) Using only the relative frequency distribution and not the raw data, what is the approximate time at which about 50% of pace- makers fail?

Answer 1

d) the count 45 is median for 89 pacemaker

and 45th frequency lies between 18 - <24 , so approximately that is time at which about 50% of pace- makers fail.