Answer:
Step-by-step explanation:
If x - 1 is a factor of the cubic, then 1 should result in 0 when you put it in the cubic for x. Does it?
f(1) = 2(1)^3 - 15(1)^2 + 22(1) + 15
f(1) = 2 - 15 + 22 + 15
f(1)= 24.
No the result is not zero. So x - 1 is not a factor.
However there must be something that makes this cubic go to zero. The easiest way to find it is to graph it.
The numbers that do make this zero are -0.5, 3, 5
Which mean that the factors are (2x+1)(x-3)(x - 5)
Answer:
Ther has been an increase in the selling time.
Step-by-step explanation:
Step 1. Specify the null hypotesis
In this case, we have to demonstrate that the selling time is now different than before the drought.
Step 2. Choose a significance level
In this problem, is 0.10
Step 3. Compute the mean
In this case, the mean of the sample is 94.
Step 4. Compute the probability value (p) of obtaining a difference between the mean of the sample and the hypothesided value of μ.
The degrees of freedom are calculated as (N-1) = (100-1) = 99. Then we can look up in the t-table (http://davidmlane.com/hyperstat/t-table.html) to calculate the probability value of a t of 1.818 with 99 degrees of freedom. The value of this probability is 0.05.
Step 5. Compare the P-value (0.05) with the significance level (0.10). Since the P-value is less than the significance level, the effect is significant.
Since the effect is significant, the null hypotesis is rejected.
It is concluded that the mean of the selling time has changed (increase) from its previous value.