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free/or 0.5$ |
| m528 | If you ask three strangers about their birthdays, what is the probability.
(a) All were born on Wednesday?
(b) All were born on different days of the week?
(c) None was born on Saturday? |
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| m529 | In 2000, the mean salary of classroom teachers in Tinora School District was $28,650. By 2009, the mean salary increased to $33,972, and further increased in 2013 to $37,382. The American Federation of Classroom Teachers maintains information on the trends throughout the United States in classroom teacher salaries. Its index, which has a base period of 2000, was 122.5 for 2009 and 136.9 for 2013. Compare the Tinora teachers to the national trends. |
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| m530 | In 2011, the United States exported a total of $281 billion worth of products to Canada. The five largest categories were:
Product Amount
Vehicles ........ $46.9
Machinery...... 44.2
Electrical machinery... 27.1
Mineral fuel and oil.... 18.4
Plastic ......... 12.6
a. Use a software package to develop a bar chart.
b. What percentage of the United States’ total exports to Canada is represented by the two categories “Mineral fuel and oil” and “Vehicles”?
c. What percentage of the top five exported products do “Mineral fuel and oil” and
“Vehicles” represent? |
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| m531 | In a binomial distribution, n 5 12 and p 5 .60. Find the following probabilities.
a. x 5 5.
b. x # 5.
c. x $ 6. |
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| m532 | In a binomial distribution, n 5 8 and p 5 .30. Find the probabilities of the following events.
a. x 5 2.
b. x # 2 (the probability that x is equal to or less than 2).
c. x $ 3 (the probability that x is equal to or greater than 3). |
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| m533 | In a binomial situation, n 5 4 and p 5 .25. Determine the probabilities of the following events using the binomial formula.
a. x 5 2
b. x 5 3 |
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| m534 | In a binomial situation, n 55 and p 5 .40. Determine the probabilities of the following events using the binomial formula.
a. x 5 1
b. x 5 2 |
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| m535 | In a management trainee program at Claremont Enterprises, 80% of the trainees are female and 20% male. Ninety percent of the females attended college, and 78% of the males at-tended college.
a. A management trainee is selected at random. What is the probability that the person selected is a female who did not attend college?
b. Are gender and attending college independent? Why?
c. Construct a tree diagram showing all the probabilities, conditional probabilities, and joint probabilities.
d. Do the joint probabilities total 1.00? Why? |
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| m536 | In a multiple regression equation, k = 5 and n = 20, the MSE value is 5.10, and SS total is 519.68. At the .05 significance level, can we conclude that any of the regression coefficients are not equal to 0? |
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| m537 | In a multiple regression equation, two independent variables are considered, and the sample size is 25. The regression coefficients and the standard errors are as follows.
b1 = 2.676 sb1 = 0.56
b2 = 20.880 sb2 = 0.71
Conduct a test of hypothesis to determine whether either independent variable has a coefficient equal to zero. Would you consider deleting either variable from the regression equation? Use the .05 significance level. |
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| m538 | In a particular metro area, there are three commercial television stations, each with its own news program from 6:00 to 6:30 p.m. According to a report in this morning’s local newspaper, a random sample of 150 viewers last night revealed 53 watched the news on WNAE (channel 5), 64 watched on WRRN (channel 11), and 33 on WSPD (channel 13). At the .05 significance level, is there a difference in the proportion of viewers watching the three channels? |
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| m539 | In a Poisson distribution m 5 0.4.
a. What is the probability that x 5 0?
b. What is the probability that x . 0? |
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| m540 | In a Poisson distribution m 5 4.
a. What is the probability that x 5 2?
b. What is the probability that x # 2?
c. What is the probability that x . 2? |
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| m541 | In a poll to estimate presidential popularity, each person in a random sample of 1,000 voters was asked to agree with one of the following statements:
1. The president is doing a good job.
2. The president is doing a poor job.
3. I have no opinion.
A total of 560 respondents selected the first statement, indicating they thought the presi-dent was doing a good job.
a. Construct a 95% confidence interval for the proportion of respondents who feel the president is doing a good job.
b. Based on your interval in part (a), is it reasonable to conclude that a majority of the population believes the president is doing a good job? |
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| m542 | In a recent study, 90% of the homes in the United States were found to have large-screen
TVs. In a sample of nine homes, what is the probability that:
a. All nine have large-screen TVs?
b. Less than five have large-screen TVs?
c. More than five have large-screen TVs?
d. At least seven homes have large-screen TVs? |
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| m543 | In a recent survey, 35% indicated chocolate was their favorite flavor of ice cream. Suppose we select a sample of 10 people and ask them to name their favorite flavor of ice cream.
a. How many of those in the sample would you expect to name chocolate?
b. What is the probability exactly four of those in the sample name chocolate?
c. What is the probability four or more name chocolate? |
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| m544 | In a sample of 200 residents of Georgetown County, 120 reported they believed the county real estate taxes were too high. Develop a 95% confidence interval for the proportion of residents who believe the tax rate is too high. Does it seem reasonable to conclude that 50% of the voters believe that taxes are too high? |
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| m545 | In an ANOVA table, MSE was equal to 10. Random samples of six were selected from each of four populations, where the sum of squares total was 250.
a. Set up the null hypothesis and the alternate hypothesis.
b. What is the decision rule? Use the .05 significance level.
c. Complete the ANOVA table, what is the value of F?
d. What is your decision regarding the null hypothesis? |
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| m546 | In an automated filling operation, the probability of an incorrect fill when the process is operated at a low speed is 0.001. When the process is operated at a high speed, the probability of an incorrect fill is 0.01. Assume that 30% of the containers are filled when the process is operated at a high speed and the remainder are filled when the process is operated at a low speed.
(a) What is the probability of an incorrectly filled container?
(b) If an incorrectly filled container is found, what is the probability that it was filled during the high-speed operation? |
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| m547 | In Chapter 19, we discuss acceptance sampling. Acceptance sampling is a statistical method used to monitor the quality of purchased parts and components. To ensure the quality of incoming parts, a purchaser or manufacturer normally samples 20 parts and allows one defect.
a. What is the likelihood of accepting a lot that is 1% defective?
b. If the quality of the incoming lot was actually 2%, what is the likelihood of accepting it?
c. If the quality of the incoming lot was actually 5%, what is the likelihood of accepting it? |
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