Chapter 1, Problem 14PT

(a)

To determine

To find: the longest battery that lasted.

Answer to Problem 14PT

5|5 will represents the 550-559 hours, which will be longest lasted battery.

Explanation of Solution

Given:

  

As per provided hint in the problem that 4|2 represents 420-429 hours, so 5|5 will represents the 550-559 hours, which will be longest lasted battery.

(b)

To determine

To find: the reason for preferring a Brand X battery

Answer to Problem 14PT

The minimum time that the battery lasts is higher for brand X (300 hours) than for brand Y(170 hours).

Explanation of Solution

On seeing the back to back stem plot, it is clear that Brand X has less variation the battery life as values are less spread from the center in comparison to Brand Y. Hence due to this reason someone can prefer Brand X instead of Brand Y

(c)

To determine

To find: the reason for preferring a Brand Y battery

Answer to Problem 14PT

Most of the batteries of brand Y have a higher lifetime than most of the batteries of bran X.

Explanation of Solution

On seeing the back to back stem plot, it is clear that Brand Y has greater values of battery life than the Brand X since it has more value corresponding to 4 . Therefore, the median lifetime will be higher for Brand Y than the Brand X. Hence due to this reason someone can prefer Brand Yinstead of Brand X.