Question

1. The results of a mathematics placement exam at two different campuses of Mercy College follow:

Campus	Sample size	Mean	Population Std. Deviation
1	1,995	50	14
2	303	47	12

What is the computed value of the test statistic?

3.0

4.0

2.0

11.9

2.

The results of a mathematics placement exam at two different campuses of Mercy College follow:

Campus	Sample size	Mean	Population Std. Deviation
1	2,631	33	15
2	300	30	13

Is there a difference in the mean score of Campus 1 and Campus 2 of Mercy College? Given that the two population standard deviations are known, what is the p-value?

1.0000

0.9651

0.0651

0.0002

3.

Accounting procedures allow a business to evaluate their inventory at LIFO (Last In First Out) or FIFO (First In First Out). A manufacturer evaluated its finished goods inventory (in $ thousands) for five products both ways. Based on the following results, is LIFO more effective in keeping the value of his inventory lower?

Product	FIFO (F)	LIFO (L)
1	231	227
2	125	106
3	106	119
4	218	206
5	254	251

What are the degrees of freedom?

12

4

16

17

Answer 1

Solution:

Question 1)

Given:

Campus	Sample size	Mean	Population Std. Deviation
1	1,995	50	14
2	303	47	12

the computed value of the test statistic

Question 2)

Campus	Sample size	Mean	Population Std. Deviation
1	2,631	33	15
2	300	30	13

what is the p-value

First find z test statistic value:

P-value = 2 X P( Z > 3.72)

P-value = 2 X [ 1 - P( Z < 3.72) ]

Look in z table for z = 3.7 and 0.02 and find area.

P( Z< 3.72) = 0.9999

Thus

P-value = 2 X [ 1 - P( Z < 3.72) ]

P-value = 2 X [ 1 - 0.9999 ]

P-value = 2 X 0.0001

P-value = 0.0002

Question 3)

Product	FIFO (F)	LIFO (L)
1	231	227
2	125	106
3	106	119
4	218	206
5	254	251

A manufacturer evaluated its finished goods inventory (in $ thousands) for five products both ways.

Since two samples are taken on same products, this is paired data ( dependent data)

Thus df = degrees of freedom for paired data = n - 1

df = n - 1

df = 5 - 1

df = 4