Quiz 2

Each question is worth 1 point.

Dont leave anything blank. I can always find a way to give you some credit if youve made an attempt. Be sure to post any questions you have after the answers open.

The work you turn in by 11:59 P.M. on Oct 2nd must be your own.

You draw two cards from a deck, what is the probability that:

both of them are face cards (king, queen, or jack)?

you draw two cards from a deck and both of them are hearts?

Assume adults have IQ scores that are normally distributed with a mean of 100 and a standard deviation of 15.

Find the probability that a randomly selected adult has IQ < 115

Find the probability that a randomly selected adult has IQ > 70

Find P30, which is the IQ separating the bottom 30% from the top 70%

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.

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?

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 doesnt matter. What is the

Probability of their winning?

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	0.02
1	0.15
2	0.29
3	0.26
4	0.16
5	0.12

Is this a probability distribution?

What is the mean?

What is the standard deviation?

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