A+ answers | Mathematics homework help

1. If you flip a coin three times, the possible outcomes are HHH, HHT, HTH, HTT, THH, THT, TTH, TTT. What is the probability that at least two heads occur consecutively?

A. 1/8

B.3/8

C. 5/8

D. 6/8

2. If you flip a coin three times, the possible outcomes are HHH, HHT, HTH, HTT, THH, THT, TTH, TTT. What is the probability of getting at least one head?

A. 4/9

B. 5/6

C. 7/8

D. 5/8

3. Joe dealt 20 cards from a standard 52-card deck, and the number of red cards exceeded the number of black cards by 8. He reshuffled the cards and dealt 30 cards. This time, the number of red cards exceeded the number of black cards by 10. Determine which deal is closer to the 50/50 ratio of red/black expected of fairly dealt hands from a fair deck and why.

A. The first series is closer because 1/10 is farther from 1/2 than is 1/8.

B. The series closer to the theoretical 50/50 cannot be determined unless the number of red and black cards for each deal is given.

C. The second series is closer because 20/30 is closer to 1/2 than is 14/20.

D. The first series is closer because the difference between red and black is smaller than the difference in the second series.

4. Suppose you buy 1 ticket for $1 out of a lottery of 1000 tickets where the prize for the one winning ticket is to be $500. What is your expected value?

A. $0.00

B. −$0.40

C. −$1.00

D. −$0.50

5. A bag contains four chips of which one is red, one is blue, one is green, and one is yellow. A chip is selected at random from the bag and then replaced in the bag. A second chip is then selected at random. Make a list of the possible outcomes (for example, RB represents the outcome red chip followed by blue chip) and use your list to determine the probability that the two chips selected are the same color. (Hint: There are 16 possible outcomes.)

A. 1/4

B. 3/4

C. 2/16

D. 3/16

6. The data set represents the income levels of the members of a country club. Estimate the probability that a randomly selected member earns at least $98,000.

112,000 126,000 90,000 133,000 94,000 112,000 98,000 82,000 147,000 182,000 86,000 105,000

140,000 94,000 126,000 119,000 98,000 154,000 78,000 119,000

A. 0.4

B. 0.6

C. 0.66

D. 0.7 7.

Suppose you have an extremely unfair coin: the probability of a head is 1/5, and the probability of a tail is 4/5. If you toss the coin 40 times, how many heads do you expect to see?

A. 8

B. 6

C. 5

D. 4

8. In a poll, respondents were asked whether they had ever been in a car accident. 220 respondents indicated that they had been in a car accident and 370 respondents said that they had not been in a car accident. If one of these respondents is randomly selected, what is the probability of getting someone who has been in a car accident? Round to the nearest thousandth.

A. 0.384

B. 0.380

C. 0.373

D. 0.370

9. If a person is randomly selected, find the probability that his or her birthday is ***** in May. Ignore leap years. There are 365 days in a year. Express your answer as a fraction.

A. 335/365

B. 334/365

C. 336/365

D. 30/365

10. The distribution of B.A. degrees conferred by a local college is listed below, by major.

Major                 Frequency

English                2073

Mathematics      2164

Chemistry            318

Physics                856

Liberal Arts        1358

Business            1676

Engineering        868

9313

What is the probability that a randomly selected degree is not in Business?

A. 0.7800

B. 0.8200

C. 0.8300

D. 0.9200

11. A class consists of 50 women and 82 men. If a student is randomly selected, what is the probability that the student is a woman?

A. 32/132

B. 25/66

C. 50/132

D. 82/132

12. A 28-year-old man pays $125 for a one-year life insurance policy with coverage of $140,000. If the probability that he will live through the year is 0.9994, to the nearest dollar, what is the man’s expected value for the insurance policy?

A. $139,916

B. −$41

C. $84

D. −$124

13. The probability that Luis will pass his statistics test is 0.94. Find the probability that he will fail his statistics test.

A. 0.02

B. 0.05

C. 0.94

D. 0.06

14. Suppose you pay $1.00 to roll a fair die with the understanding that you will get back $3.00 for rolling a 5 or a 2, nothing otherwise. What is your expected value?

A. $1.00

B. $0.00

C. $3.00

D. −$1.00

15. Jody checked the temperature 12 times on Monday, and the last digit of the temperature was odd six times more than it was even. On Tuesday, she checked it 18 times and the last digit was odd eight times more than it was even. Determine which series is closer to the 50/50 ratio of odd/even expected of such a series of temperature checks.

A. The Monday series is closer because 1/6 is closer to 1/2 than is 1/8.

B. The Monday series is closer because 6/12 is closer to 0.5 than is 8/18.

C. The Tuesday series is closer because the 13/18 is closer to 0.5 than is 9/12.

D. The series closest to the theoretical 50/50 cannot be determined without knowing the number of odds and evens in each series.

16. A die with 12 sides is rolled. What is the probability of rolling a number less than 11? Is this the same as rolling a total less than 11 with two six-sided dice? Explain.

A. 2/6

B. 3/6

C. 4/6

D. 5/6

17. A bag contains 4 red marbles, 3 blue marbles, and 7 green marbles. If a marble is randomly selected from the bag, what is the probability that it is blue?

A. 2/11

B. 3/11

C. 5/14

D. 3/14

18. In the first series of rolls of a die, the number of odd numbers exceeded the number of even numbers by 5. In the second series of rolls of the same die, the number of odd numbers exceeded the number of even numbers by 11. Determine which series is closer to the 50/50 ratio of odd/even expected of a fairly rolled die.

A. The second series is closer because the difference between odd and even numbers is greater than the difference for the first series. B. The first series is closer because the difference between odd and even numbers is less than the difference for the second series.

C. Since 1/2 > 1/5 > 1/11, the first series is closer.

D. The series closer to the theoretical 50/50 cannot be determined unless the total number of rolls for both series is given.

19. A study of two types of weed killers was done on two identical weed plots. One weed killer killed 15% more weeds than the other. This difference was significant at the 0.05 level. What does this mean?

A. The improvement was due to the fact that there were more weeds in one study.

B. The probability that the difference was due to chance alone is greater than 0.05.

C. The probability that one weed killer performed better by chance alone is less than 0.05.

D. There is not enough information to make any conclusion.

20. A sample space consists of 46 separate events that are equally likely. What is the probability of each?

A. 1/24

B. 1/46

C. 1/32

D. 1/18

21. A researcher wishes to estimate the proportion of college students who cheat on exams. A poll of 490 college students showed that 33% of them had, or intended to, cheat on examinations. Find the margin of error for the 95% confidence interval.

A. 0.0432

B. 0.0434

C. 0.0425

D. 0.0427

22. Among a random sample of 150 employees of a particular company, the mean commute distance is 29.6 miles. This mean lies 1.2 standard deviations above the mean of the sampling distribution. If a second sample of 150 employees is selected, what is the probability that for the second sample, the mean commute distance will be less than 29.6 miles?

A. 0.8849

B. 0.5

C. 0.1131

D. 0.1151

23. Eleven female college students are selected at random and asked their heights. The heights (in inches) are as follows:

67, 59, 64, 69, 65, 65, 66, 64, 62, 64, 62

Estimate the mean height of all female students at this college. Round your answer to the nearest tenth of an inch if necessary.

A. It is not possible to estimate the population mean from this sample data

B. 64.3 inches

C. 64.9 inches

D. 63.7 inches

24. The scatter plot and best-fit line show the relation between the price per item (y) and the availability of that item (x) in arbitrary units. The correlation coefficient is -0.95. Determine the amount of variation in pricing explained by the variation in availability.

A. 5%

B. 10%

C. 95%

D. 90%

25. Select the best estimate of the correlation coefficient for the data depicted in the scatter diagram.

A. 0.60

B. -0.97

C. 0.10

D. -0.60

26. The scatter plot and best-fit line show the relation among the data for the price of a stock (y) and employment (x) in arbitrary units. The correlation coefficient is 0.8. Predict the stock price for an employment value of 6.

A. 8.8

B. 6.2

C. 8.2

D. None of the values are correct

27. A random sample of 30 households was selected from a particular neighborhood. The number of cars for each household is shown below. Estimate the mean number of cars per household for the population of households in this neighborhood. Give the 95% confidence interval.

A. 1.14 to 1.88

B. 1.12 to 1.88

C. 1.12 to 1.98

D. 1.14 to 1.98

28. The scatter plot and best-fit line show the relation among the number of cars waiting by a school (y) and the amount of time after the end of classes (x) in arbitrary units. The correlation coefficient is -0.55. Determine the amount of variation in the number of cars not explained by the variation time after school.

A. 55%

B. 70%

C. 30%

D. 45%

29. A population proportion is to be estimated. Estimate the minimum sample size needed to achieve a margin of error E = 0.01with a 95% degree of confidence.

A. 7,000

B. 8,000

C. 9,000

D. 10,000

30. Which graph has two groups of data, correlations within each group, but no correlation among all the data?

a)

b)

c)

d)

31. Select the best fit line on the scatter diagram below.

A. A

B. B

C. C

D. None of the lines is the line of best fit

32. Write possible coordinates for the single outlier such that it would no longer be an outlier.

A. (23, 18)

B. (20, 5)

C. (15, 15)

D. (12, 15)

33. The scatter plot and best-fit line show the relation among the number of cars waiting by a school (y) and the amount of time after the end of classes (x) in arbitrary units. The correlation coefficient is -0.55. Use the line of best fit to predict the number of cars at time 4 after the end of classes.

A. 7.0

B. 6.0

C. 8.0

D. 3.5

34. The graph shows a measure of fitness (y) and miles walked weekly. Identify the probable cause of the correlation.

A. The correlation is coincidental.

B. There is a common underlying cause of the correlation.

C. There is no correlation between the variables.

D. Walking is a direct cause of the fitness.

35. Select the best fit line on the scatter diagram below.

A. A

B. B

C. C

D. All of the lines are equally good

36. Among a random sample of 500 college students, the mean number of hours worked per week at non-college related jobs is 14.6. This mean lies 0.4 standard deviations below the mean of the sampling distribution. If a second sample of 500 students is selected, what is the probability that for the second sample, the mean number of hours worked will be less than 14.6?

A. 0.5

B. 0.6179

C. 0.6554

D. 0.3446

37. Sample size = 400, sample mean = 44, sample standard deviation = 16. What is the margin of error? 
A. 1.4

B. 1.6

C. 2.2

D. 2.6

38. 30% of the fifth grade students in a large school district read below grade level. The distribution of sample proportions of samples of 100 students from this population is normal with a mean of 0.30 and a standard deviation of 0.045. Suppose that you select a sample of 100 fifth grade students from this district and find that the proportion that reads below grade level in the sample is 0.36. What is the probability that a second sample would be selected with a proportion less than 0.36?

A. 0.8932

B. 0.8920

C. 0.9032

D. 0.9048

39. Select the best estimate of the correlation coefficient for the data depicted in the scatter diagram.

A. -0.9

B. 0.9

C. 0.5

D. -0.5

40. Of the 6796 students in one school district, 1537 cannot read up to grade level. Among a sample of 812 of the students from this school district, 211 cannot read up to grade level. Find the sample proportion of students who cannot read up to grade level.

A. 0.14

B. 0.26

C. 211

D. 0.23