Question

MNBA is a company that sells chem-lab supplies. In the past, customers had spent an average of $6,800 annually, but management believes that the number has decreased in the last year. In order to test this, one manager looks at a sample of 40 customers' spending last year. The results can be found in the file ASpending, Hypothesis Testing. The manager would like to test her hypothesis at an alpha level of 0.1. She also believes that the standard deviation has not changed, so she is using a population standard deviation value of 1450.

data points

5,001
3,769
7,746
4,300
7,338
8,621
6,868
8,117
5,674
8,083
7,489
6,136
5,450
6,185
3,708
8,101
7,628
6,392
9,234
6,907
6,009
8,083
4,662
6,089
4,483
5,637
7,369
6,196
6,358
6,387
6,140
9,358
7,168
5,385
4,939
6,254
5,799
4,642
5,773
5,650

1. What would be appropriate hypotheses?

Ho: μ≥6800

Ha: μ<6800

Ho: x≥6800

Ha: x<6800

Ho: μ≥6378.2

Ha: μ<6378.2

Ho: x≥6378.2

Ha:

2. What type of test is this?

Left (lower) tailed

Right (upper) tailed

3 tailed

2 tailed

3. What is the critical value, z,  the test statistic, and the p-value?

4. Conclusion fill in blanks. Since p is    blank 1 ["less than", "greater than"]  alpha,   blank 2 ["accept", "do not reject", "reject"]   the null hypothesis. There    blank 3 ["is not", "is"]         enough evidence to conclude that the amount customers spend annually blank 4 ["is more than$ 6378.2", "is less than $6800.", "is less than $6378.2", "is more than $6800."]      

Answer 1

	5,001
	3,769
	7,746
	4,300
	7,338
	8,621
	6,868
	8,117
	5,674
	8,083
	7,489
	6,136
	5,450
	6,185
	3,708
	8,101
	7,628
	6,392
	9,234
	6,907
	6,009
	8,083
	4,662
	6,089
	4,483
	5,637
	7,369
	6,196
	6,358
	6,387
	6,140
	9,358
	7,168
	5,385
	4,939
	6,254
	5,799
	4,642
	5,773
	5,650
Total	255,128
n	40
xbar=Total/n	6378.2

1.

2. Left (lower) tailed

3.

4.

Since p is ["less than"]  alpha,  ["reject"]   the null hypothesis. There ["is"] enough evidence to conclude that the amount customers spend annually ["is less than $6800."]