There are 100 years in a century
Answer:
For this case we know that the confidence level is 90% so then the significance level is 
and 
. And we can find in the normal standard distribution a value who accumulates 0.5 of the area on each tail and we got:
And the best option would be:
1.645
Step-by-step explanation:
We assume that the parameter of interest is 
and we can assume that the distribution for this parameter is normally distributed so then the confidence interval assuming a two sided interval is given by:
Where 
represent the estimator for the parameter, SE the standard error and 
the critical value.
For this case we know that the confidence level is 90% so then the significance level is and . And we can find in the normal standard distribution a value who accumulates 0.5 of the area on each tail and we got:
And the best option would be:
1.645
Answer:
The correct answer is 3πcm
Step-by-step explanation:
The length of an arc is calculated using the formula P=∅/360×2πr
where ∅is the angle the arc subtends at the center of the circle, and r is the radius of the circle of which the arc is part.
2r gives the diameter which from the diagram corresponds to AB=36 cm
therefore P=30/360×π×36
=3πcm
