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Originally Posted by DLI848  I just need help with these 3 problems. If you could give me the steps on a TI84 or TI83 calculator that would be awesome!
The answer to this question is 2.31%, but I don't know how to get to it using my TI-84 calculator. I'm almost sure I have to use normcdf for it:
1)Assume that the weights of quarters are normally distributed with a mean of 5.75g and a standard deviation 0.083g. A vending machine will only accept coins weighing between 5.52g and 5.92g. What percentage of legal quarters will be accepted?
The answer to this question is 0.24:
2) At a California college, 22% of students speak Spanish, 5% speak French, and 3% speak both languages. What is the probability that a student chosen at random from the college speaks Spanish or French?
The answer to this question is 0.279
According to the U.S. census, in 2005 21% of homicide victims were known to be female, 9.7% were known to be under the age of 18 and 2.8% were known to be females under the age of 18. What is the probability that a murder victim was known to be female or under the age of 18 based on these 2005 estimates? |
#1) Okay, your first basic equation is P(5.52<x<5.92)= ?
Now, because your Z tables are going to be in the form P(z<c), you have to re-arrange your equation.
P(5.52<x<5.92) = (1-p(x < 5.52))-(1-p(x < (5.92))
now, put your equation in standard form using z = (x-mean)/standard deviation
1 - p[z1 < ((5.25-mean)/s.d.)] - [1 - p[z2 < ((5.92-mean)/s.d.)]] = ?
look up the answers for your c value in the z tables, so you'll get a final equation of probability 1 - probability 2 = ?
p1-p2 = .24
that's all I have time to do right now, I'm in my business communication class.
