Module 6 prelims & module quiz

Which of the following questions represent continuous random variables?

A. How long does it take your to get from your residence to school?

B. How many credits are you taking?

C. What is your GPA?

D. How many courses have you withdrawn from?

A. How long does it take your to get from your residence to school?
C. What is your GPA?

Match the wording of each phrase with the correct mathematical inequality or equation.

___fewer than 5

___at most 5

___greater than or equal to 5

___higher than 5

___less than or equal to 5

___at least 5

1.x > 5

2.x < 5

3.x >= 5

4.x <= 5

2,4,3,1,4,3

Select all of the true statements about finding probabilities with continuous distributions.

A. The total area under the curve, which represents the continuous distribution, will sum to one.

B. P(v < X < w) = the area under the continuous distributions probability function, between the values of v and w.

C. for any value k, P(X = k) = 0 because there is no area under a single point

D. a Binomial distribution is an example of a continuous distribution

A. The total area under the curve, which represents the continuous distribution, will sum to one.

B. P(v < X < w) = the area under the continuous distributions probability function, between the values of v and w.

C. for any value k, P(X = k) = 0 because there is no area under a single point

The Standard normal distribution has a .....

A. mean of 1 and standard deviation of 0

B. mean of 1 and standard deviation of 1

C. mean of 0 and standard deviation of 1

D. mean of 0 and standard deviation of 0

E. unknown mean and unknown standard deviation

C. mean of 0 and standard deviation of 1

If a distribution has a mean of 50 and a standard deviation of 15, then a score of 63 will have a z-score of...

-0.867

59.7

45.8

0.867

0.867

A distribution has a mean of 300 and a standard deviation of 21.  A specific value in this distribution has a z-score of 1.5.   How many standard deviations is this specific value from the mean?

1.5

According to the Empirical Rule, what percent of the z-distribution will be between z = -1 and z = 1?

50%

68%

75%

95%

68%

According to the Empirical rule, 95% of the z-distribution should be between z-scores of ...

0 and 2

-3 and 0

-1 and 1

-2 and 2

-3 and 3

-2 and 2

A distribution is normally distributed with a mean of 500 and a standard deviation of 75. According to the Empirical Rule, what percent of the data in this distribution should lie between the values of 350 and 650?

50%

68%

95%

99.7%

95%

A distribution is normally distributed with a mean of 500 and a standard deviation of 75. According to the Empirical Rule, what percent of the data in this distribution should lie between the values of 425 and 575?

50%

68%

95%

99.7%

68%

A distribution is normally distributed with a mean of 300 and a standard deviation of 25. According to the Empirical Rule, what percent of the data in this distribution should lie between the values of 225 and 375?

50%

68%

95%

99.7%

99.7%

Three brands of lightbulbs are being tested. Each brand has lifetimes that are normally distributed.

Brand A has a mean lifetime of 1600 hours with a standard deviation of 50 hours.

Brand B has a mean lifetime of 1520 hours with a standard deviation of 100 hours.

Brand C has a mean lifetime of 1580 hours with a standard deviation of 80 hours.

Which brand of lightbulb is most likely to have a lightbulb that has a lifetime of 1720 hours?

Brand A

Brand B

Brand C

Brand C

A distribution is normally distributed with a mean of 70 and a standard deviation of 15. According to the Empirical Rule, about 95% of the values in this distribution should be between what two values?

55 and 85

40 and 100

60 and 80

25 and 115

65 and 75

40 and 100

A distribution is normally distributed with a mean of 850 and a standard deviation of 50. According to the Empirical Rule, about 68% of the values in this distribution should be between what two values?

835 and 865

845 and 855

825 nd 875

800 and 900

750 and 950

800 and 900

Two professors gave a statisitcs exam. Professor Ashur's exam had a mean score of 80 with a standard deviation of 5. Professor Beewear's exam had a mean score of 60 with a standard deviation of 10.

Malik got a score of 72 on his statistics exam. Whose class is Malik more likely from?

Professor Ashur

Professor Beewear

Cannot tell from the given information

Professor Beewear