Answer:
8+3+7=18
probability of brown m&m is
Sally is planning the school picnic and needs to decide what food vendor to use. She asks 250 students whether they would rather
have a taco truck or a fruit smoothie cart. The results of the survey are shown in the table. Taco truck Fruit smoothies Total Eighth-graders 75 45 120 Ninth-graders 105 25 130 Total 180 70 250 What is the relative frequency of eighth-graders who want fruit smoothies?
1 answer:
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SOLUTION
The mean is 4min
standard deviation is 1min
the z score is
where
then we have
The probability the call lasted less than 3 min will be
Therefore, the probability that (z < -1 ) is
[tex]\begin{gathered} Pr(z<-1)=Pr(0Hence, the percentage of the calls that lasted less than 3 min is 16%