# Project #34152 - Stats test

Find the indicated probability or percentage for the normally distributed variable.

The variable X is normally distributed. The mean is μ = 15.2 and the standard deviation is σ = 0.9.
Find P(X > 16.1).

 0.1357 0.1587 0.8413 0.155

3.3 points

Question 2

1.

2.

3.  Find the mean for the given sample data. Unless otherwise specified, round your answer to one more decimal place than that used for the observations.

Frank's Furniture employees earned \$340.75, \$394.04,  , and  last week. Find the mean wage of the employees. Round your answer to the nearest cent.

4.

 \$305.99 \$355.19 \$367.19 \$458.98

5.

6.

3.3 points

Question 3

1.

2.

3.  Provide an appropriate response.

A newly-premiered play just ended that evening at a local theater. Theater management briefly interviews every eighth person leaving the theater to see if that person will recommend the play at that theater to other people. Identify the type of sampling used in this example.

4.

 Systematic sampling Stratified sampling Multistage sampling Cluster sampling

5.

6.

3.3 points

Question 4

1.

2.

3.

4.  Obtain the five-number summary for the given data.

The test scores of 15 students are listed below.

5.

6.

 42, 54, 70.0, 87, 95 42, 52.50, 68, 85.5, 95 42, 54, 68, 87, 95 42, 52.50, 70.0, 85.5, 95

7.

8.

3.3 points

Question 5

1.

2.

3.  Use a table of areas to find the specified area under the standard normal curve.

The area that lies to the right of 0.59

4.

 0.219 0.7224 0.2224 0.2776

5.

6.

3.3 points

Question 6

1.

2.

3.  Identify the study as an observational study or a designed experiment.

A clinic gives a drug to a group of ten patients and a placebo to another group of ten patients to find out if the drug has an effect on the patients' illness.

4.

 Designed experiment Observational study

5.

6.

3.3 points

Question 7

1.

2.

3.  Find the indicated binomial probability. Round to five decimal places when necessary.

What is the probability that 6 rolls of a fair die will show four exactly 2 times?

4.

 0.20094 0.0134 0.0067 0.41667

5.

6.

3.3 points

Question 8

1.

2.

A magazine publisher mails a survey to every subscriber asking about the timeliness of its subscription service. The publisher finds that only 5% of the subscribers responded. This 5% represents what?

4.

 The population The sample

5.

6.

3.3 points

Question 9

1.

2.

3.  Use a table of areas for the standard normal curve to find the required z-score.

Find the z-score for having area 0.07 to its right under the standard normal curve, that is, find z0.07.

4.

 1.39 1.45 1.48 1.26

5.

6.

3.3 points

Question 10

1.

2.

3.  Find the indicated probability. Round to four decimal places.

A test consists of 10 true/false questions. To pass the test a student must answer at least 8 questions correctly. If a student guesses on each question, what is the probability that the student will pass the test?

4.

 0.9893 0.0107 0.0547 0.0439

5.

6.

3.3 points

Question 11

1.

2.

3.  Find the mean of the random variable.

The random variable X is the number of houses sold by a realtor in a single month at the Sendsom's Real Estate office. Its probability distribution is given in the table. Round the answer to two decimal places when necessary.

4.

 3.35 3.6 3.4 3.5

5.

6.

3.3 points

Question 12

1.

2.

3.  Provide an appropriate response.

The finalists in an essay competition are        and  Consider these finalists to be a population of interest. The possible samples (without replacement) of size three that can be obtained from this population of six finalists are as follows.

L,M,B L,M,D L,M,E L,M,J L,B,D L,B,E
L,B,J L,D,E L,D,J L,E,J M,B,D M,B,E
M,B,J M,D,E M,D,J M,E,J B,D,E B,D,J
B,E,J D,E,J

If a simple random sampling method is used to obtain a sample of three of the finalists, what are the chances of selecting Ben, Danny, and Joan?

4.

5.

6.

3.3 points

Question 13

1.

2.

3.  Find the indicated probability by using the general addition rule.

If you pick a card at random from a well shuffled deck, what is the probability that you get a face card or a spade?

4.

5.

6.

3.3 points

Question 14

1.

2.

3.  Solve the problem. If necessary, round your answer to one more decimal place than that used for the observations.

A scientist used the following data set showing the weight in pounds gained (or lost) by a sample of eight laboratory animals given Drug X. Determine n, , and

8.9 -7.5 2.1 3.0
-2.9 2.4 5.7 -5.4

4.

 n = 10;   = 6.3;   = 0.63 n = 8;   = 6.3;   = 0.79 n = 10;   = 6.3;   = 0.79 n = 8;   = 6.3;   = 0.63

5.

6.

3.3 points

Question 15

1.

2.

3.  Solve the problem.

A sample of 55 eggs yields a mean weight of 1.76 ounces. Assuming that , find the margin of error in estimating μ at the 95% level of confidence.

4.

 0.07 oz 0.47 oz 0.06 oz 0.01 oz

5.

6.

3.3 points

Question 16

1.

2.

3.  Provide an appropriate response.

Find the population standard deviation. Round to one decimal place as needed.

0, -2, 4, 6

4.

 10 3.2 1.8 7.2

5.

6.

3.3 points

Question 17

1.

2.

3.  Identify the study as an observational study or a designed experiment.

An educational researcher used school records to determine that, in one school district, 84% of children living in two-parent homes graduated high school while 75% of children living in single-parent homes graduated high school.

4.

 Designed experiment Observational study

5.

6.

3.3 points

Question 18

1.

2.

3.  Find the specified probability.

A statistics professor has office hours from 9:00 am to 10:00 am each day. The number of students waiting to see the professor is a random variable, X, with the distribution shown in the table.

The professor gives each student 10 minutes. Determine the probability that a student arriving just after 9:00 am will have to wait no longer than 30 minutes to see the professor.

4.

 0.4 0.95 0.8 0.25

5.

6.

3.3 points

Question 19

1.

2.

3.  Find the indicated probability by using the general addition rule.

For a person selected randomly from a certain population, events A and B are defined as follows.

A = event the person is male
B = event the person is a smoker

For this particular population, it is found that   and  Find  Round approximations to two decimal places.

4.

 0.41 0.56 0.86 0.71

5.

6.

3.3 points

Question 20

1.

2.

3.  Use a table of areas for the standard normal curve to find the required z-score.

Find the z-score for which the area under the standard normal curve to its left is 0.40

4.

 0.25 0.57 -0.25 -0.57

5.

6.

3.3 points

Question 21

1.

2.

3.  Find the indicated probability by using the special addition rule.

A card is drawn from a well-shuffled deck of 52 cards. What is the probability of drawing an ace or a 6?

4.

 7

5.

6.

3.3 points

Question 22

1.

2.

3.  Use a table of areas to find the specified area under the standard normal curve.

The area that lies between -0.73 and 2.27

4.

 0.4884 1.54 0.7557 0.2211

5.

6.

3.3 points

Question 23

1.

2.

3.  Solve the problem.

A confidence interval for a population mean has a margin of error of 6.4. Determine the length of the confidence interval.

4.

 6.4 40.96 3.2 12.8

5.

6.

3.3 points

Question 24

1.

2.

3.  Find the expected value of the random variable. Round to the nearest cent unless stated otherwise.

In a game, you have a  probability of winning  and a  probability of losing  What is your expected value?

4.

 \$10.15 -\$8.78 -\$7.41 \$1.37

5.

6.

3.3 points

Question 25

1.

2.

3.  Use a table of areas to find the specified area under the standard normal curve.

The area that lies to the left of 1.13

4.

 0.8907 0.8485 0.1292 0.8708

5.

6.

3.3 points

Question 26

1.

2.

3.  Find the necessary sample size.

Scores on a certain test are normally distributed with a variance of 68. A researcher wishes to estimate the mean score achieved by all adults on the test. Find the sample size needed to assure with 95 percent confidence that the sample mean will not differ from the population mean by more than 4 units.

4.

 66 8 17 1111

5.

6.

3.3 points

Question 27

1.

2.

3.  Calculate the specified probability

Suppose that W is a random variable. Given that P(W ≤ 6) = 0.975, find P(W > 6).

4.

 0.025 6 0.975 0

5.

6.

3.3 points

Question 28

1.

2.

3.  Find the requested confidence interval.

A college statistics professor has office hours from 9:00 A.M. to 10:30 A.M. daily. A sample of waiting times to see the professor (in minutes) is 10, 12, 20, 15, 17, 10, 30, 28, 35, 28, 19, 27, 25, 22, 33, 37, 14, 21, 20, 23. Assuming  find the 95.44% confidence interval for the population mean.

4.

 18.8 to 25.8 minutes -7.7 to 7.8 minutes 19.5 to 35.1 minutes -3.5 to 3.5 minutes

5.

6.

3.3 points

Question 29

1.

2.

3.  Determine the possible values of the random variable.

Suppose a coin is tossed four times. Let X denote the total number of tails obtained in the four tosses. What are the possible values of the random variable X?

4.

 1, 2, 3 0, 1, 2, 3, 4 HHHH, HHHT, HHTH, HHTT, HTHH, HTHT, HTTH, HTTT, THHH, THHT, THTH, THTT, TTHH, TTHT, TTTH, TTTT 1, 2, 3, 4

5.

6.

3.3 points

Question 30

1.

2.

3.  Find the sample standard deviation for the given data. Round your final answer to one more decimal place than that used for the observations.

Christine is currently taking college astronomy. The instructor often gives quizzes. On the past seven quizzes, Christine got the following scores.

52 15 48 27 12 42 68

4.

 20.6 48 12,494 9956.6

 Subject Mathematics Due By (Pacific Time) 06/27/2014 03:00 pm
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