STAT 200 Quiz 2
MathematicsExpertQuiz 2
Each question is worth 1 point.
1. You draw two cards from a deck, what is the probability that:
a. Both of them are face cards (king, queen, or jack)?
b. You draw two cards from a deck and both of them are hearts?
2. Assume adults have IQ scores that are normally distributed with a mean of 100 and a standard deviation of 15.
a. Find the probability that a randomly selected adult has IQ < 115
b. Find the probability that a randomly selected adult has IQ > 70
c. Find P30, which is the IQ separating the bottom 30% from the top 70%
3. a. When would the mean grade in a class on a final exam be considered a statistic?
b. When would it be considered a parameter?
c. Define bias in terms of expected value.
d. Is it possible for a statistic to be unbiased yet very imprecise? Can it be accurate but biased?
4. a. Why is a 99% confidence interval wider than a 95% confidence interval?
b. When you construct a 95% confidence interval, what are you 95% confident about?
5. My parents lived in Florida and wanted to know the probability of winning the Florida Fantasy 5 if they bought one ticket. They had to pick the five winning numbers from 1-36. Each randomly selected number is different and order doesn’t matter. What is the Probability of their winning?
6. In a study of families with children with disabilities, group of 6 US households were randomly selected. In the table below, the random variable x represents the number of households among 6 that had a child with a disability living there.
x | P(x) |
0 | 0.539 |
1 | 0.351 |
2 | 0.095 |
3 | 0.014 |
4 | 0.001 |
5 | 0+ |
6 | 0+ |
a) Is this a probability distribution?
b) What is the mean?
c) What is the standard deviation?
7. Ten peas are generated from parents having the green/yellow pair of genes so there is a 75% probability that an individual pea will have a green pod. Find the probability that among the 10 offspring peas, at least 9 have green pods. Is this unusual? Explain.
8. Find the critical value:
a. Z0.02
b. Z0.01
c. Z0.10
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