Growth Spurt: It is generally known that boys grow at an unusually fast rate between the ages of about 12 and 14

.Following are heights, in inches of

10

boys, measured at age

12

and again at age

14

.

Age 12	Age 14
63.3	69.6
62.7	67.5
67.5	73.7
59.2	64.9
61.4	67.0
60.7	65.5
55.9	62.1
59.7	65.4
56.3	61.5
63.0	68.5
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Part 1 of 2

(a) Construct a

99.9%

confidence interval for the mean increase in height for boys between the ages of

12

and

14

.Let

d

represent the height at age

14

minus the height at age

12

. Use the TI-84 calculator to find the critical value and round the answers to at least two decimal places.

A 99.9% confidence interval for the mean increase in height for boys between 12 and 14 is <d< .