Chapter 1.2, Problem 47E

(a)

To determine

To find:the preference between twostem plot

Answer to Problem 47E

Stem plot with split is preferred over stem plot without split as the former

Explanation of Solution

Given:

628	669	740	651	710	736	717	698	653	604	781	784
790	811	830	858	858	896	806	790	792	957	872

Calculation:

To make a stem plot of these rainfall amounts, first round the data to the nearest 10.

Stem-plot diagram of rainfall amount

(i) The stem plot without split.

Steam	Leaf
6	0	3	5	5	7
7	0	1	2	4	4	8	8	9	9
8	1	1	3	6	6	7
9	0	5

(ii) The stem plot with split

Steam	Leaf
6	0	3
6	5	5	7
7	0	1	2	4	4
7	8	8	9	9	9
8	1	1	3
8	6	6	7
9	0
9	5

Conclusion:

Therefore, Stem plot with split is preferred over stem plot without split as the former.

(b)

To determine

To describe: the shape, center and spread of distribution

Answer to Problem 47E

Shape: symmetric

Center: 7

Spread: 6 to 9

Explanation of Solution

The shape of split stem plot has single peak at 7. The range of distribution is from 6 to 9. The shape of distribution is symmetric.

Shape: symmetric

Center: 7

Spread: 6 to 9

(c)

To determine

To find: the effecton monsoon rainfall

Answer to Problem 47E

Average of rainfall amount is 767

Explanation of Solution

Calculation:

The average of rainfall amount El Nino years between 1871 and 2004 is:

  $\frac{sumoftheobservations}{totalnumberofobservations}$ = $\frac{1}{23}$ (628 + 669 + 740 + … + 957 + 872)

= $\frac{17631}{23}$

  $\approx 767$

Conclusion:

Therefore,average of rainfall amount is 767.