Lena purchased a prepaid phone card for $20. Long distance calls cost 21 cents a minute using this card, Lena used her card only
1 answer:
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ANSWER
C. 7
EXPLANATION
We want to evaluate
We use the order of operations PEDMAS.
Dealing with the parenthesis first,we have
Note that:
and
Our expression now becomes:
Next, we add to get:
We finally subtract to get,
The correct answer is C
The marginal distribution for gender tells you the probability that a randomly selected person taken from this sample is either male or female, regardless of their blood type.
In this case, we have total sample size of 714 people. Of these, 379 are male and 335 are female. Then the marginal probability mass function would be
where G is a random variable taking on one of two values (male or female).