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In a list of numbers, 20.0 is 2 standard deviation above the mean, while 6.5 is 3 standard deviation below the mean.

Quantity A

The average of the list of numbers

Quantity B

14.6




The table above summarizes customer satisfaction ratings for two banks, where each rating is an integer from 1 to 10. Which of the following statements must be true?

Indicate all such statements.


The random variable X has the standard normal distribution with a mean of 0 and a standard deviation of 1, as shown. Probabilities, rounded to the nearest 0.01, are indicated for the six intervals shown. The random variable Y has a normal distribution with a mean of 2 and a standard deviation of 1. Using the probabilities shown, approximately how much greater is the probability that the value of Y is between 1 and 2 than the probability that the value of X is between 1 and 2?
In a normal distribution of data x, the mean is 400, while the standard deviation is 60.

Quantity A

P(400 < x < 430)

Quantity B

P(430 < x < 460)


For a certain normal distribution, its mean and standard deviation are 50 and 5.4, respectively.

Quantity A

The number of data in (45, 48.6)

Quantity B

The number of data in (55.4, 59)


Data set A and B are both normally distributed. In data set A, the mean is 60, standard deviation is 9, and 72 is $$q$$th percentile. In data set B, the mean is 70, standard deviation is 6, and 78 is $$w$$th percentile.

Quantity A

$$q$$

Quantity B

$$w$$




The figure above shows a normal distribution with mean m and standard deviation d, including approximate percents of the distribution corresponding to the six regions shown.

The lengths of phone calls made on a certain weekend by students at High School H are approximately normally distributed with a mean of 30 minutes and a standard deviation of 10 minutes. Which of the following statements must be true?

Indicate all such statements.
Let x be a positive number. The random variable R is normally distributed with mean x and standard deviation 0.25x. The random variable T is normally distributed with mean 0.5x and standard deviation 0.5x.

Quantity A

P (R <1.375x)

Quantity B

P (T <1.25x)




The figure shows a normal distribution with mean m and standard deviation d, including approximate percents of the distribution corresponding to the six regions shown.

The random variable Y is normally distributed with mean 576. If the value 628 is at the $$84^{th}$$ percentile of the distribution of Y, which of the following is the best estimate of the value at the $$98^{th}$$ percentile of the distribution of Y?
A normal distribution with mean 50, $$16^{th}$$ percentile: 42,$$33^{th}$$ percentile: q.

Quantity A

q-42

Quantity B

50-q


Let W be a continuous random variable such that P (W > $$\frac{1}{2}$$)=$$\frac{9}{10}$$ and P (W > $$\frac{3}{4}$$)=$$\frac{7}{20}$$. What is the value of P ($$\frac{1}{2}$$ < W ≤ $$\frac{3}{4}$$)?

Give your answer as a fraction.
The probability distribution function $$f$$ of a continuous random variable $$x$$ is defined by $$f(x) = \frac{2}{13}|x|$$ for $$−3 \leq x \leq 2$$

Quantity A

The median of the distribution of $$x$$

Quantity B

-$$\frac{9}{5}$$


Sets R, S and T are finite and T contains more elements than S. The number of elements in T minus the number of elements in S is equal to the number of elements in the set R∩T minus the number of elements in the set R∩S.

Quantity A

The number of elements in the set R∪S

Quantity B

The number of elements in the set R∪T


Let S and T be two sets such that the ratio of the number of elements in S to the number of elements in T to the number of elements in the set S∩T is 4 to 3 to 1. If the sum of the number of elements in S but not in T and the number of elements in T but not in S is 2520, what is the number of elements in S∩T?
In a group of 100 adults, each owns a DVD player, a CD player, or both. If 60 adults own a DVD player and 70 adults own a CD player, how many adults own both?
In a group of people, 15% have license, 10% have parking tickets, while 78% have neither license nor parking tickets. What percent of people have both license and parking tickets?
Among 25 parents, 14 have at least 1 boy, 15 have at least 1 girl

Quantity A

The number of parents who have at least 1 boy but no girl

Quantity B

10


In a survey, employees who want to switch jobs were asked what issues were most important in choosing another job. Half of those surveyed said "salary" and 35% said "location". If 32 percent of those surveyed said both "salary" and "location", what percent said either "salary" or "location" but not both?
The recreation director at a local youth club surveyed the members to determine interest in two activities-a hiking trip and a softball game. Of the members surveyed, 60 percent were interested in the hiking trip and 75 percent were interested in the softball game. Of those who were interested in the softball game, $$\frac{2}{3}$$ were also interested in the hiking trip. What percent of the members surveyed were not interested in either of the two activities?
In a herd of 90 cows, some are brown, some are white, and the rest are both brown and white. In the herd, 55 cows are entirely or partially white, and 75 cows are entirely or partially brown. If the cows are randomly selected for inoculation, what is the probability that the first cow selected will be entirely white?

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