Question 1

Which of the following best describes the relationship shown in the scatterplot below?

(Refer to the fourth image above.)

Accepted Answer

The variables appear to have a negative and very strong relation.

Question 2

Which scatter diagram best represents a correlation coefficient of $$r = -0.812$$?

Accepted Answer

Fifth scatterplot (bottom right)

Question 3

Suppose you roll a pair of standard dice. What is the probability that the sum is 6, given that both dice do not show the same number?

Accepted Answer

$$\frac{4}{30} = \frac{2}{15}$$

Question 4

A bag contains 6 red marbles, 3 blue marbles, and 7 green marbles. If a marble is randomly selected, what is the probability that it is blue?

Accepted Answer

$$\frac{3}{16}$$

Question 5

If events $$E$$ and $$F$$ are independent, $$P(E) = 0.1$$ and $$P(F) = 0.7$$, what is $$P(E 	ext{ and } F)$$?

Accepted Answer

0.07

Question 6

A probability distribution has $$\mu_X = 3.97$$ and $$\sigma_X = 1.89. $$Which formula correctly calculates the standard deviation of a probability distribution?

Accepted Answer

$$\sigma_X = \sqrt{\sum[x^2$ \cdot P(x)] - \mu_X^2$}$$

Question 7

A manager wants to know if there is a linear relationship between years of service and average monthly sales. The correlation coefficient is $$r = 0.632. $$Using Table VI, does a linear relation exist?

Accepted Answer

No, a linear relation does not exist.

Question 8

A probability model is valid if:

Accepted Answer

All probabilities are between 0 and 1 inclusive and the sum of the probabilities equals 1.

Question 9

The weights of certain machine components are normally distributed with a mean of $$8.98 g $$and a standard deviation of $$0.05 g. $$What is the 97th percentile?

Accepted Answer

$$9.07 g$$

Question 10

Suppose a brewery's filling machine pours beer with a mean of $$12.23 oz $$and a standard deviation of $$0.04 oz. $$What fill amount corresponds to the highest 1.5% of fill amounts?

Accepted Answer

$$12.317 oz$$

Question 11

The lengths of human pregnancies are approximately normally distributed with a mean of $$268$$ days and a standard deviation of $$15$$ days. What is the probability that a pregnancy lasts at least $$300$$ days?

Accepted Answer

$$0.0166$$

Question 12

A card is drawn from a standard deck. What is the probability that the card is a club, given the card is not a spade?

Accepted Answer

$$\frac{13}{39} = \frac{1}{3}$$

Question 13

A probability distribution for the number of oranges purchased is given. What is the mean number of oranges purchased?

Accepted Answer

$$3.97$$

Question 14

For a normal curve with $$\mu = 42$$ and $$\sigma = 4$$, at which values do the inflection points occur?

Accepted Answer

$$38$$ and $$46$$

Question 15

A manager is selected at random from a company. What is the probability that the manager has a Master's or Ph.D.?

Accepted Answer

$$0.2938$$

Question 16

Find the area under the standard normal curve to the right of $$z = 0.97.$$

Accepted Answer

$$0.1660$$

Question 17

A probability distribution is given for the number of oranges purchased. What is the probability that a customer purchased three or more oranges?

Accepted Answer

$$0.76$$

Question 18

Suppose events $$A$$ and $$B$$ are mutually exclusive with $$P(A) = 0.3$$ and $$P(B) = 0.7. $$What is the probability that either $$A or$$ $$B$$ will occur?

Accepted Answer

1

Question 19

A normal distribution has $$\mu = 42$$ and $$\sigma = 4. $$What percentage of the area under the normal curve is between $$34$$ and $$50$$?

Accepted Answer

95%

Comprehensive Step-by-Step Guidance for STAT C1000 Review Exam #2

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