Answer:
1. 690
2. Do not reject the null hypothesis.
Step-by-step explanation:
1. Month t
At the end of Feb 6
March 4
April 4
May 4
June 2
14th of July 2
Total 24
Therefore on 14th July, t = 24
Forecast: Y = 450+10t = 450 + 10*24 = 450+240 = 690
2. Options are "a. Reject the null hypothesis. b. Do not reject the null hypothesis. c. Take a larger sample. d. Reserve judgment"
In general, if test statistic is more extreme than the critical values at given level of significance then we reject the null hypothesis otherwise we do not reject the null hypothesis.
Here, test statistic for the given two tailed test is Z = -1.07 and critical value at level of significance α = 0.5 is ± 1.96 . Since -1.96<Z<1.96, we can say that we do not reject Null Hypothesis as the test statistic is not extreme than the critical value at given level of significance.