Answer:
See explanation below
Step-by-step explanation:
Here, a director of manufacturing must convince management that a proposed manufacturing method reduces costs before the new method can be implemented. The current production method operates with a mean cost of $220 per hour.
a) The alternative and null hypotheses would be:
H0: μ ≥ 220
Ha: μ < 220
b) Comment on the conclusion when H0 cannot be rejected:
When we fail to reject the null hypothesis H0, there is not enough evidence to conclude that the mean cost can be reduced from $220. Therefore the manager's proposed method cannot be implemented.
c) Comment on the conclusion when H0 can be rejected:
When the null hypothesis, H0 is rejected, there is enough evidence to conclude that the mean cost can be reduced from from $220. Therefore the manager's proposed method can be implemented.
3.25 is the answer so copy down the answer its right
Answer:
The lower bound for a 90% confidence interval for the percentage of all American adults who believe in ghosts is 0.3549
Step-by-step explanation:
In a sample with a number n of people surveyed with a probability of a success of 
, and a confidence level of 
, we have the following confidence interval of proportions.
In which
z is the zscore that has a pvalue of 
.
For this problem, we have that:
90% confidence level
So 
, z is the value of Z that has a pvalue of 
, so 
.
The lower limit of this interval is:
The lower bound for a 90% confidence interval for the percentage of all American adults who believe in ghosts is 0.3549
A decrease of 8.25% means the reduction factor is 100-8.25=91.75%=0.9175.
The shrinkage over 15 years is 0.9175¹⁵=0.27485 approx, so the size of the forest will be 3100×0.27485=852 sq km approx.
