Answer: B. 11%
Step-by-step explanation:
Let A = Event that students eat breakfast in the morning.
B= Event that students floss their teeth.
We are given P(A)=57%=0.57
P(B)=80%=0.80
P(A∩B) = 46% =0.46
Now, the probability that a student from this class eats break feast but does not floss their teeth :-

Hence, the probability that a student from this class eats break feast but does not floss their teeth= 11%
Answer:
A sample of 1032 is needed.
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
.
The margin of error is:

A sample of 300 components showed that 20 were defective.
This means that 
99% confidence level
So
, z is the value of Z that has a pvalue of
, so
.
How large a sample is needed to estimate the true proportion of defective components to within 2.5 percentage points with 99% confidence?
A sample of n is needed.
n is found when M = 0.025. So






Rounding up
A sample of 1032 is needed.
Step-by-step explanation:
7/9×9/10
63/20
3 3/20
.....