Question

   (CH. 9-3) Below is a recording of predicted high temperatures (using a 5 day forecast) and actual recorded high temperatures. Use a 0.01 significance level to test the claim that there is a difference between the forecasted temps and the actual temps.

         

Date	7/1	7/2	7/3	7/4	7/5	7/6	7/7	7/8	7/9	7/10
Forecast	68	73	73	85	84	79	79	78	81	80
Actual High Temperature	72	79	82	80	80	81	77	72	78	80
DIFFERENCE

• Write each statement.

• H_o(null hypothesis):
• H₁(alternative hypothesis):

• Write the Critical Value here:

• Write the “test statistic” here:

• Write the P-value here:

• REJECT H_o:   YES or NO

What is your conclusion?

Answer 1

Here we have paired data so paired t test will be used. Let d = Forecast - Actual

Following table shows the calculations:

Forecast	Actual	d	(d-mean)^2
68	72	-4	15.21
73	79	-6	34.81
73	82	-9	79.21
85	80	5	26.01
84	80	4	16.81
79	81	-2	3.61
79	77	2	4.41
78	72	6	37.21
81	78	3	9.61
80	80	0	0.01
Total		-1	226.9

Conclusion: There is no evidence to conclude that there is  a difference between the forecast temps and the actual temps.