Exam #4 - critical thinking

Given an urn containing 4 red balls, 2 blue balls, and 3 yellow balls. What is the probability of drawing either a red ball or a blue ball on a single draw?

a. 2/3

14. In reference to TableA, what is the median length of service?

a. 3 years

According to the principle of indifference,

a. All possible outcomes of an event are equally probable.

Suppose a quality control inspector pulls every tenth can of soup from a conveyor belt to ensure that the cans are filled to capacity. How should this procedure be evaluated?

a. The sample may not be a random sample.

Given an urn containing 2 green, 3 white, and 4 red balls. If two balls are drawn and the first ball is not replaced before the second is drawn, what is the probability that the first ball is white and the second is red?

d. 1/6

Suppose an irregular 7-sided solid object, having sides numbered 1 through 7, is rolled 100 times, and side 4 turns up 12 times. What is the approximate probability of this event happening?

b. .12

Suppose that the lengths of employment (in years) of 7 employees of a small company are as follows: 1, 2, 2, 3, 4, 4, 5. What is the approximate variance for this set of data?

b. 1.7

On one roll of a pair of dice, what is the probability of the points adding up to 5?

b. 1/9

In reference to TableA, what is the modal (Most occurred) length of service?

b. 2 years.

If the odds of the Yankees beating the Red Sox are 5 to 3, what is the probability of this event happening?

b. 5/8

Given an urn containing 3 red balls and 4 white balls. If two balls are drawn and the first ball is not replaced before the second is drawn, what is the probability that both balls are red?

d. 1/7

What is the probability of drawing a blackjack from a poker deck (no jokers) on a single draw?

c. 1/26

In reference to TableA, what is the mean length of service of the employees?

c. 3.2 years.

Given the event described in question 9, what is the probability that the two balls are the same color?

c. 5/18

If the odds of the Steelers beating the Chiefs are 7 to 4, what is the probability of this event happening?

c. 7/11

A sample that is not representative of the population from which it is drawn is said to be:

c. Biased.

To compute the probability of drawing two aces from a poker deck (without replacing the first card before drawing the second) the theory of probability that would normally be used is the:

c. Classical (a priori) theory.

Suppose that a poll is taken about how marriage partners relate to each other, and one of the questions asked is if the person being interviewed has ever lied to his/her spouse. Can the responses to this question be trusted?

c. No, because interviewers who have lied to their spouse would probably deny it.

Suppose that the age of 8 kittens in a pet shop are as follows: 1, 2, 2, 3, 3, 4, 4, 5. What is the variance for this set of data?

d. 1.5

Suppose that a biologist took water samples at random intervals from a rapidly flowing creek to test for contaminants. A sample was taken at a single location from the center of the creek for one year. Could such a survey be depended on? a. Yes, because contaminants in the creek would not change from

d. Probably.

Suppose a poll is taken to sample voter preferences in an upcoming presidential election. To conduct the poll, an interviewer standing on a street corner in the financial district of a large city asks questions of people as they pass by. What result would be expected from such a poll?

d. The responses would be biased in favor of the Republican candidate.

In regard to the event described in question 2, what are the odds?

e. 3 to 22

What is the probability of getting at least 1 head on 3 successive tosses of a coin?

e. 7/8

If the standard deviation of a set of data is relatively small, then

e. Most of the data fall close to the mean point.

For the set of data in question 19, what is the standard deviation?

e. √1.5

For the set of data in question 17, what is the approximate standard deviation?

e. √1.7