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Tutors Answer Your Questions about Probability-and-statistics (FREE)
Question 136545This question is from textbook math
: hi i need help to this problem
together, carmen molini and jay mccarroll can prepare a catered dinner in 20 hours. working alone, carmen can do the job 5 hours faster than jay. find the time that each person takes to prepare a catered dinner. round to the nearest tenth.
thank you This question is from textbook math
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Question 136532: A sample of 20 pages was taken without replacement fromthe 1,591-page phone directory Ameritech Pages Plus Yellow pages
On each page, the mean area devoted to display ads was measured (a display as is a large block of multicolored illustrations, maps, and text). The data (in square millimeters) are shown below:
0; 260; 356; 403; 536; 0; 268; 369; 428; 536; 268;
396; 469; 536; 162; 338; 403; 536; 536; 130
a construct a 95% confidence interval for the true mean
b Why might normatlity be an issue here? c. What sample size would be needed to obtain an error of _+ 10 square millimeters with 99% confidence
d. If this is no a reasonable requirement, suggest one that is. (Data are from a project by MBA student Daniel R. Dalach)
I am new to this and have not been formally trained! Please help.
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Question 136315: The management of the corporation looking at training issues are not convinced that they should switch to toutside consultants for all of their training programs. They want to look at how the two groups compared on the pretest. The relevant data are given below.
Population 1 Population 2
Outside Consultant In House trainer
Sample
Size 30 40
Mean Score on Pretest 4.8 5.2
Std. Dev. on Pretest Score 0.3 0.4
Test to see if there is a mean difference in the pretest scores. Use Alpha 0.05
Ho
H1
Alpha
CV
What Formula?
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Question 136683This question is from textbook Algebra 2
: You are performing an expirement to determine how well plants grow under different light sources. Out of the 30 plants in the expirement, 12 receive visible lights, 15 receive ultraviolet light, and 6 receive both visible and ultraviolet light. What is the probability that a plant in the expirement receives either visible light or ultraviolet light?This question is from textbook Algebra 2
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Question 136637: 11. A survey of industrial salespeople who are either self-employed, work for small, medium-sized, or large firms revealed the following with respect to incomes:
Of those who earn less than $20,000, 9 are self-employed, 12 are employed by small firms, 40 by medium size firms, and 89 by large firms.
Of those who earn $20,000 to $39,999, 11 are self-employed, 10 are employed by small firms, 45 by medium size firms, and 104 by large firms.
Of those who earn $40,000 or more, 10 are self-employed, 13 are employed by small firms, 50 by medium size firms, and 107 by large firms.
Using the .05 level of significance, use a chi-square test to test the hypothesis that there is no relationship between the income level of the industrial salespeople and their employment status. Be sure to state the critical value, the test statistic value, and your interpretation of the test results.
12. Multiple regression uses quantitative values to represent variables that are numeric in nature, but occasionally the use of qualitative variables are used to represent conditions of interest. In those cases, the researcher would use (circle one):
a. dummy variables c. systemic variables
b. non-systemic variables d. insulating variables
Thank you, this class is over!
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Question 136703: The mean length of a small counterbalance bar is 43 millimeters. The production supervisor is concerned that the adjustments of the machine producing the bars have changed. He asks the Engineering Department to investigate. Engineering selects a random sample of 12 bars and measures each. The results are reported below in millimeters:
42 39 42 45 43 40 39 41 40 42 43 42
Is it reasonable to conclude that there has been a change in the mean length of the bars? Use the .02 level of significance. Show all 5 steps – interpret your conclusion!
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Question 136634: Please help
5. The following information was gathered for a One-Way ANOVA test at the .05 level of significance:
Treatment 1 Treatment 2 Treatment 3
9 13 10
7 20 9
11 14 15
9 13 14
12 12 15
The critical value for this test is (circle one) : a. 3.68 b. 3.34 c. 3.18 d. 3.89
6. What is the value of the F statistic in the ANOVA test in question 5 above? _____
7. True or False. A data set resulted in a regression equation of Y = 17.08 - 1.16x From the equation we can determine that the X variable is directly related to the Y variable.
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Question 136557: You are interested in whether men participate more than women in political activities, so you survey 632 men and 675 women and ask them how many political events they attended within the past year. Here are your results:
MEN WOMEN
mean = 1.58 mean = 1.42
s.d. = 0.10 s.d. = 0.23
N=432 N=375
With 95% confidence what do you conclude?
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Question 136636: 10. James Profit wants to take National Widget Company public. He is interested in the relationship between the size of the initial public offering and the price per share. A sample of 10 companies that recently went public revealed the following information:
size ($millions) price per share
9.0 10.0
13.0 12.4 a. The regression equation is: __________
11.0 10.5
14.0 12.8 b. The coefficient of correlation is: ______
8.0 13.6
9.0 11.5 c. The coefficient of determination is: ____
10.0 14.2
12.0 9.7 d. What would Y equal if X equals13? ______
10.0 12.3
7.0 9.6
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Question 136631: Please help:
1. A production manager is conducting a Z test of her assembly line. She collects a sample of 64 items from the assembly line and determines that the test’s critical value is +1.96 and the Z statistic is +1.73. Based on this information she should (circle one): Accept Reject the Null hypothesis.
2. Smith Widget Company makes widgets for the medical industry. One particular customer requires widgets that meet FDA standards. One FDA standard requires Z-testing of at least 100 widgets at a time at the .08 level of significance. The specific standard requires that widgets be no smaller than a certain tolerance and no larger than a certain tolerance. The critical value(s) for such a test would be: __________
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Question 136632: 3. The same production manager in question 1 above decides to use a smaller sample size of just 25 items. If she conducts a 2-tailed test at the 90 percent level of confidence, her critical value(s) would be: ________
4. National Packing Materials Company claims its X20 box can hold loads up to at least 80 pounds. Smith Widget Company has been using the boxes for one year and feels the boxes fail at lighter loads. Hearing the complaints from Smith, the lead engineer for National Packaging decides to test the company’s claim that it can hold at least 80 pounds. He decides to text 64 boxes at the .05 level of significance. He finds a mean of 78 pounds with a standard deviation of 5 pounds. What is the critical value for this test?_______ What is the value of the test statistic? ___________ What is the Null hypothesis? ___________ What is the alternate hypothesis? ____________ What is the standard error of the mean? ______________ Should the Null hypothesis be accepted or rejected? __________
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Question 136635: 8. A technique used to arrive at the regression equation by minimizing the sum of the squares of the vertical differences between the actual Y values and the predicted Y values is known as the ______________.
9. A condition that occurs in multiple regression analysis if the independent variables are themselves correlated is known as: a. autocorrelation b. stepwise regression
c. multicorrelation d. multicollinearity
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Question 136605: In a Texas study, researchers gave lovastatin to 2,325 people and an inactive substitute to 2,081 people (average age 58). After 5 years, 57 of the lovastatin group had suffered a heart attack, compared with 97 for the inactive pill.
(a) State the appropriate hypotheses.
(b) Obtain a test statistic and p-value. Interpret the results at α = .01.
(c) Is normality assured?
(d) Is the difference large enough to be important?
(e) What else would medical researchers need to know before prescribing this drug widely?
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Question 136827: 1)A weight-loss clinic guarantees that its new customers will lose at least 5 lb by the end of their first month of participation or their money will be refunded. If the loss of weight of customers at the end of their first month is normally distributed, with a mean of 6.8 lb and a standard deviation of 0.81 lb, find the percent of customers who will be able to claim a refund.
Please Help!
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Question 136825: a)Find the standard deviation of the following set of data.
180, 187, 175, 186, 177, 196, 166
b)The results on an English exam are normally distributed. the z-scores for some of the students are shown below.
Jan 1.3 Kim 1.8 Lou -1.1 May 0.0
Nan 1.1 Fay -1.7 Gia 1.1 Sue -1.8
Which of the students scored below the mean?
Thanka in advance
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Question 136824: A newspaper article reported that people spend a mean of hours per day watching TV, with a standard deviation of hours. A psychologist would like to conduct interviews with the of the population who spend the most time watching TV. She assumes that the daily time people spend watching TV is normally distributed. At least how many hours of daily TV watching are necessary for a person to be eligible for the interview? Carry your intermediate computations to at least four decimal places. Round your answer to at least one decimal place.
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Question 136796: Not sure about this!
An auditor reviewed 25 oral surgery insurance claims from a particular surgical office, determining that the mean out-of-pocket patient billing above the reimbursed amount was $275.66 with a standard deviation of $78.11.
(a) At the 5 percent level of significance, does this sample prove a violation of the guideline that the average patient should pay no more than $250 out-of-pocket?
State your hypotheses and decision rule.
(b) Is this a close decision?
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Question 136792: 9.54 - Please solve
Faced with rising fax costs, a firm issued a guideline that transmissions of 10 pages or more should be sent by 2-day mail instead. Exceptions are allowed, but they want the average to be 10 or below. The firm examined 35 randomly chosen fax transmissions during the next year, yielding a sample mean of 14.44 with a standard deviation of 4.45 pages. (a) At the .01 level of significance, is the true mean greater than 10? (b) Use Excel to find the right-tail p-value.
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Question 136834: A newspaper spent a mean of 7.5 hours watching tv per day with a standard deviation of 2.1 hours. A psychologisit conducted interviews with 10% of the population who watched tv. She assumes that the tim watching tv is normally distributed. How many hours of daily tv is ncessary for a person to be eligible for the interview. Carry your intermediate comoputations to at least four decimal places. Round your answer to at least one decimal place.
Thank you.
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Question 136794: Need assistance with this -
The Web-based company Oh Baby! Gifts has a goal of processing 95 percent of its orders on the same day they are received. If 485 out of the next 500 orders are processed on the same day, would this prove that they are exceeding their goal, using α = .025? (See story.news.yahoo.com accessed June 25, 2004.)
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Question 136842: Suppose that the heights of adult women in the United States are normally distributed with a mean of 63.5 inches and a standard deviation of 2.3inches. Jennifer is taller than 75%of the population of U.S. women. How tall (in inches) is Jennifer? Carry your intermediate computations to at least four decimal places. Round your answer to at least one decimal place.
Thanks,
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Question 136858This question is from textbook fundamentals of mathematics
: 8. a football coach has five guards and seven tackles trying out for the squad.as a final cut, five of these players will be cut at random. find the probablity that the group of players cut will
a. consist of guards only
b. consist of tackles only
c. consist of three guards and two tackles
d.consist of four tackles and one guard
e. consist of three tackles and two guards
f. consist of four guards and one tackle
10. a case of soda pop contains six bottles of root beer, six bottles of orange soda, seven bottles of cola, and five bottles of gingerale. If you select three bottles at random find the probability that
a. all three bottles are cola
b. all three bottles are rootbeer
c. two bottles are gingerale and one bottle is cola
d. one bottle is orange soda, and two bottles are rootbeer
e. one bottle is cola, one bottle is orange soda, and one bottle is gingerale
f. one bottle is cola, one bottle is orange soda, and one bottle is rootbeerThis question is from textbook fundamentals of mathematics
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Question 136805: Need help having problems solving this problem
The engineer in a widget factory wants to test out a new form of raw materials. So a batch of widgets are made in the old manner as a control group and then a batch are made with the new materials as a comparison. If the widget weight is statistically the same on both sets, the new materials will be used. The weights of the 10 old process widgets and the 10 new process widgets are seen below.
Old New
36.19 36.20
35.80 36.62
36.00 36.03
36.19 36.40
36.18 36.44
36.11 36.02
36.13 36.12
36.48 36.56
35.98 36.05
36.40 36.44
1. Define this situation as either a 2 sample test or a paired test. Why?
2. Calculate a test statistic
3. Calculate a p-value
1. Give an accurate statement as to whether or not the new widget material should be used. Use a significance level of 0.05.
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Question 136942This question is from textbook Fundamentals of Mathematics
: I am working on this problem and I would like to see if I had worked it out correctly. Could you please help me. So I may continue to work the others problem.
Question: A football coach has five guards and seven tackles trying out for the squad. As a final cut, five of these players will be cut at random. Find the probability that the group of players cut will
a. Consist of guards only
b. Consist of tackles only
c. Consist of three guards and two tackles
d. Consist of four tackles ans one guard
e. Consist of three tackles and two guards
f. Consist fo four guards and one tackle
My answer are:
A. 5/5= 1
b. 5/7
c. 3/5 * 2/7 = 6/35
d. 4/7 * 1/5 = 4/35
e. 3/7 * 2/5 = 6/35
f. 4/5 * 1/7 = 4/35This question is from textbook Fundamentals of Mathematics
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Question 136833: The prices of the 21 top-rated 28-inch direct view television sets are as follows.
230, 320, 450, 550, 640, 710, 810,
270, 370, 470, 560, 670, 760, 820,
310, 420, 520, 600, 680, 810, 860
Determine Q1
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Question 136793: Looking for help!
A coin was flipped 60 times and came up heads 38 times. (a) At the .10 level of significance, is the coin biased toward heads? Show your decision rule and calculations. (b) Calculate a p-value and interpret it.
Thanks
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Question 137008: 1)A six-sided die is rolled 30 times and the numbers 1 through 6 appear as shown in the
following frequency distribution. At the .10 significance level, can we conclude that the die
is fair?
Outcome Frequency Outcome Frequency
1 3 4 3
2 6 5 9
3 2 6 7
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Question 137006: 1)The null hypothesis and the alternate are:
H0: The cell categories are equal.
H1: The cell categories are not equal.
Category fo
A 10
B 20
C 30
a. State the decision rule, using the .05 significance level.
b. Compute the value of chi-square.
c. What is your decision regarding H0?
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Question 137014: The chief of security for the Mall of the Dakotas was directed to study the problem of missing goods. He selected a sample of 100 boxes that had been tampered with and ascertained that for 60 of the boxes, the missing pants, shoes, and so on were attributed to shoplifting. For 30 other boxes employees had stolen the goods, and for the remaining 10 boxes he blamed poor inventory control.
In his report to the mall management, can he say that shoplifting is twice as likely to be the cause of the lossas compared with either employee theft or poor inventory control and that employee theft and poor inventory control are equally likely? Use the 0.02 level.
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Question 137037: 1)School planners in 1995 gave the following planning estimates for the growth of the student population for the next 9 years. Perform a goodness of fit to see if their estimates were accurate.
Planning Year
Actual Size
Expected
Size
1Planning Year
798Actual Size
798Expected Size
2Planning Year
876Actual Size
872Expected Size
3Planning Year
950Actual Size
955Expected Size
4Planning Year
1044Actual Size
1046Expected Size
5Planning Year
1025Actual Size
1144Expected Size
6Planning Year
1232Actual Size
1254Expected Size
7Planning Year
1477Actual Size
1371Expected Size
8Planning Year
1531Actual Size
1503Expected Size
9Planning Year
1655Actual Size
1645Expected Size
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Question 137022: n how many ways can Al, Bob, Carlos, Don, Ed, and Fern be seated in a row of six seats if Al and Bob are not to be seated side by side? [Hint: Either Al and Bob will be seated side by side or they will not be seated side by side.]
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Question 137019: The license plates for a certain state consist of two letters followed by a five - digit number such that the first digit of the number is not zero. An example for two letters and four digits is PK-2446. (If the problem has no solution, enter NONE in the answer box.)
(a) How many different license plates can be produced?
(b) How many different plates do not have a repeated letter?
(c) How many plates do not have any repeated digits in the number part of the plate?
(d) How many plates do not have a repeated letter and also do not have any repeated digits?
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Older solutions: 1..45, 46..90, 91..135, 136..180, 181..225, 226..270, 271..315, 316..360, 361..405, 406..450, 451..495, 496..540, 541..585, 586..630, 631..675, 676..720, 721..765, 766..810, 811..855, 856..900, 901..945, 946..990, 991..1035, 1036..1080, 1081..1125, 1126..1170, 1171..1215, 1216..1260, 1261..1305, 1306..1350, 1351..1395, 1396..1440, 1441..1485, 1486..1530, 1531..1575, 1576..1620, 1621..1665, 1666..1710, 1711..1755, 1756..1800, 1801..1845, 1846..1890, 1891..1935, 1936..1980, 1981..2025, 2026..2070, 2071..2115, 2116..2160, 2161..2205, 2206..2250, 2251..2295, 2296..2340, 2341..2385, 2386..2430, 2431..2475, 2476..2520, 2521..2565, 2566..2610, 2611..2655, 2656..2700, 2701..2745, 2746..2790, 2791..2835, 2836..2880, 2881..2925, 2926..2970, 2971..3015, 3016..3060, 3061..3105, 3106..3150, 3151..3195, 3196..3240, 3241..3285, 3286..3330, 3331..3375, 3376..3420, 3421..3465, 3466..3510, 3511..3555, 3556..3600, 3601..3645, 3646..3690, 3691..3735, 3736..3780, 3781..3825, 3826..3870, 3871..3915, 3916..3960, 3961..4005, 4006..4050, 4051..4095, 4096..4140, 4141..4185, 4186..4230, 4231..4275, 4276..4320, 4321..4365, 4366..4410, 4411..4455, 4456..4500, 4501..4545, 4546..4590, 4591..4635, 4636..4680, 4681..4725, 4726..4770, 4771..4815, 4816..4860
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