Statistics
Quincy3900
StatisticsWord.docxFull Name:
Bus224
Exam-2
Total Points: 100
Read carefully before starting your exam
1. The file name Exam-2.xlsx, sheet named Part 1 is kept blank. Use Part 1 sheet to answer this question. Put a box around your answers. For (a) and (b), round your answers to 4 decimal places.
The Wall Street Journal reported some interesting statistics on the job market. One statistic is that 40% of all workers say they would change jobs for “slightly higher pay.” Suppose 20 workers are randomly selected and asked if they would change jobs for “slightly higher pay.”
a) What is the probability that nine or more say yes?
b) What is the probability that exactly six say yes?
c) What is the expected [mean] number of workers that would say they would change jobs for slightly higher pay?
[Hint: Use binomial distribution to answer question 1]
[7.5 + 5 + 2.5 = 15 points]
2. The file name Exam-2.xlsx, sheet named Part 2 is kept blank. Use Part 2 sheet to answer this question. Put a box around your answers. For (a), (b), and (c), round your answers to 4 decimal places. Put a box around your answers.
Suppose that the number of ounces of soda put into a soft-drink can is normally distributed with mean = 12.05 ounces and standard deviation = 0.03 ounce.
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(a) |
What fraction of cans will contain at least 12 ounces of soda? |
|
(b) |
What fraction of cans will contain less than 11.9 ounces of soda? |
3.
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(c) |
What fraction of cans will contain between 12 and 12.08 ounces of soda? |
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(d) |
One percent of all cans will weigh more than what value?
|
[5 +2. 5 + 10 + 12.5 = 30 points]
3. The file Exam-2.xlsx, sheet named Flaws, lists the discrete distribution of the number of flaws found in a porcelain cup produced by a manufacturing firm. Use these data and the associated probabilities to compute the expected (mean) number of flaws and the standard deviation of flaws.
[Note: Use Excel to calculate the expected value and the standard deviation of flaws. Show your work on Flaws sheet. Do not create a new sheet or a new workbook.]
[5 + 10 = 15 points]
4. Use Part 4 sheet to answer this question. Put a box around your answers.
A bicycle company makes two mountain bike models that each come in three colors. The following table shows the production volumes for last week:
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|
Color |
||
|
Model |
Blue |
Brown |
White |
|
XB-50 |
288 |
93 |
210 |
|
FL-99 |
32 |
220 |
128 |
a) Based on the relative frequency assessment method, what is the probability that a manufactured item is brown? [Round your answer to 4 decimal places]
b) What is the probability that a product manufactured is a blue or brown? [Round your answer to 4 decimal places]
c) Given that a product manufactured is white, what is the probability that item is XB-50? [Round your answer to 4 decimal places]
[2.5 + 12.5 + 10 = 25 points]
5. Use Poisson sheet to answer this question.
Suppose that X, the number of customers arriving each hour at the only checkout counter in a local pharmacy, is approximately Poisson distributed with mean = 20 customers per hour. Find the probability that X is more than 24. Round your answer to 4 decimal places. Put a box around your answer.
[15 points]
1
