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The next three questions refer to the following information:
In a survey at Kirkwood Ski Resort the following information was recorded:
0 – 10 | 11 - 20 | 21 - 40 | 40+ | |
Ski | 10 | 12 | 30 | 8 |
Snowboard | 6 | 17 | 12 | 5 |
Suppose that one person from of the above was randomly selected.
Find the probability that the person was a skier or was age 11 – 20.
$\frac{\text{77}}{\text{100}}$
Find the probability that the person was a snowboarder given he/she was age 21 – 40.
$\frac{\text{12}}{\text{42}}$
Explain which of the following are true and which are false.
The average length of time a person with a broken leg wears a cast is approximately 6 weeks. The standard deviation is about 3 weeks. Thirty people who had recently healed from broken legs were interviewed. State the distribution that most accurately reflects total time to heal for the thirty people.
$N(\text{180},\text{16}\text{.}\text{43})$
The distribution for $X$ is Uniform. What can we say for certain about the distribution for $\overline{X}$ when $n=1$ ?
A
The distribution for $X$ is uniform. What can we say for certain about the distribution for $\sum X$ when $n=50$ ?
C
The next three questions refer to the following information:
A group of students measured the lengths of all the carrots in a five-pound bag of baby carrots. They calculated the average length of baby carrots to be 2.0 inches with a standard deviation of 0.25 inches. Suppose we randomly survey 16 five-pound bags of baby carrots.
State the approximate distribution for $\overline{X}$ , the distribution for the average lengths of baby carrots in 16 five-pound bags. $\overline{X}\text{~}$
$N(2\text{,}\frac{\text{.25}}{\sqrt{\text{16}}})$
Explain why we cannot find the probability that one individual randomly chosen carrot is greater than 2.25 inches.
Find the probability that $\overline{x}$ is between 2 and 2.25 inches.
0.5000
The next three questions refer to the following information:
At the beginning of the term, the amount of time a student waits in line at the campus store is normally distributed with a mean of 5 minutes and a standard deviation of 2 minutes.
Find the 90th percentile of waiting time in minutes.
7.6
Find the median waiting time for one student.
5
Find the probability that the average waiting time for 40 students is at least 4.5 minutes.
0.9431
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