Answer:
We need a sample size of at least 650
Step-by-step explanation:
We have that to find our 
level, that is the subtraction of 1 by the confidence interval divided by 2. So:
Now, we have to find z in the Ztable as such z has a pvalue of 
.
So it is z with a pvalue of 
, so 
Now, find the margin of error M as such
In which 
is the standard deviation of the population and n is the size of the sample.
In this problem:
We need a sample of size at least n
n is found when 
So
Rounding up
We need a sample size of at least 650
Answer:
16x <= 80
It's D
16x= 16$ for each hat
80= the most he can spend
In context: Each hat cost 16$ and the most he can spend is 80, nothing more than that.
I'm pretty sure that the answer is 13/40
Step-by-step explanation:
Probability of event A on the condition of event B is:
P(A|B) = P(A and B) / P(B)
P(scored an A | girl) = P(scored an A and girl) / P(girl)
P(scored an A | girl) = 0.35 / 0.45
P(scored an A | girl) = 0.778
The probability that a randomly selected girl also scored an A is 77.8%.
Well if the gift card is worth $20 and your total expenses come to $30. That means you have to pay $10. No way around that sorry
