Answer:
The appropriate null hypothesis is 
The appropriate alternative hypothesis is 
Step-by-step explanation:
Exactly a year prior to this poll, in June of 2004, it was estimated that roughly 1 out of every 4 U.S. adults believed (at that time) that the war in Iraq was the most important problem facing the country.
At the null hypothesis, we test if the proportion is still the same, that is, of 
. So
We would like to test whether the 2005 poll provides significant evidence that the proportion of U.S. adults who believe that the war in Iraq is the most important problem facing the U.S. has decreased since the prior poll.
Decreased, so at the alternative hypothesis, it is tested if the proportion is less than 0.25, that is:
Answer:
Step-by-step explanation:
Given : A new catalyst is being investigated for use in the production of a plastic chemical. Ten batches of the chemical are produced. The mean yield of the 10 batches is 72.5% and the standard deviation is 5.8%. Assume the yields are independent and approximately normally distributed.
To find : A 99% confidence interval for the mean yield when the new catalyst is used ?
Solution :
Let X be the yield of the batches.
We have given, n=10 , 
, s=5.8%
Since the size of the sample is small.
We will use the student's t statistic to construct a 995 confidence interval.
From the t-table with 9 degree of freedom for 
The 99% confidence interval is given by,
Answer:
101
Step-by-step explanation:
Answer:
19.504
Step-by-step explanation:
divide the mass value by 2.205
B .....................................................
