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Tutors Answer Your Questions about Probability-and-statistics (FREE)
Question 173396: From the ski lodge example, suppose that the probability of breaking your leg is 0.20. (Therefore the probability of not breaking your leg is (1 – 0.20) = 0.80.) What is the probability that exactly 2 out of 5 people will break their leg? n = 5, x = 2, p = .2, q = .8. What is the probability that less than 2 out of 5 people will break their leg?
Click here to see answer by stanbon(26259)   |
Question 173645: 1. Find the probability of 7 tomatos getting accepting in 6 stores when the mean is 5.5
2.Random sample of 120 customers’s spent an average of 9.2 hours on their professional job with a sample standard deviation of 5.1 hours. Calculate the specification hours with confidence of 95%.
3.In a set of 10 samples of bike, the mileage were listed as follows
41, 42, 45, 42, 47, 59, 55, 60, 40, 35
What percent of samples are getting more than 40 mileages?
Click here to see answer by stanbon(26259) |
Question 173497: A sample of 20 pages was taken without replacement from the 1,591-page phone directory Ameritech Pages Plus Yellow Pages. On each page, the mean area devoted to display ads was measured (a display ad 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 percent confidence interval for the true mean.b) Why might normality be an issue here?(c) What sample size would be needed to obtain an error of ±10 square millimeters with 99 percent confidence? (d) If this is not a reasonable requirement, suggest one that is.
Click here to see answer by Edwin McCravy(2920) |
Question 174301: compute the geometric and harmonic means for the following distribution of annual death rates:
xi[3.95,4.95,5.95,6.95,7.95,8.95,9.95,10.95,11.95,12.95,13.95]
Fi[1 ][ 4][5 ][13 ][12] [19] [13] [10] [6 ] [4 ] [ 1 ]
Click here to see answer by Edwin McCravy(2920) |
Question 174340: 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?
Click here to see answer by Mathtut(3670) |
Question 174375: Faced with rising fax costs, a firm issued a guideline that transmission 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? NO
(b) Use Excel to find the right-tail p-value.
(a) At the .01 level of significance, is the true mean greater than 10?
Click here to see answer by stanbon(26259) |
Question 174374: 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.
Click here to see answer by stanbon(26259) |
Question 174373: 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?
Click here to see answer by stanbon(26259) |
Question 174412: I've completed some of the questions - however I am not sure if they are correct. Your assistance with these 8 questions will be greatly appreciated.
Parametric and Nonparametric Data Identification Assignment
Label each of the following situations “P” if it is an example of parametric data or “NP” if it is an example of nonparametric data.
1. A manufacturer produces a batch of memory chips (RAM) and measures the mean-time-between-failures (MTBF). The manufacturer then changes a manufacturing process and produces another batch and again measures the MTBF. Did the change to the process improve the MTBF? _NP_
2. From a written survey where the respondents were asked to rate an individual on a scale of 1 to 5, one group rated an individual a 3.7, another group rated the individual a 4.3. Is the difference statistically significant? __P__
3. A catering company is buying equipment in order to set up their own store. They have a choice of two ovens that they can purchase for the store. The used oven is $100 less than the new oven, but its heating calibration is off by 20 degrees. Which one is a better buy for them? ____
4. Jim Smith owns three real estate offices in Anytown. He has decided to open one more office, but he cannot decide between Hometown or Uptown as the town where he wants to locate. He will be comparing the mean number of homes sold per real estate agent, and the mean commission percentage earned by agents in the two towns to make his decision. _P_
5. A study to determine if job absenteeism is distributed evenly over the week. _NP_
6. Mel’s Diner has been surveying their customers for the past couple of years about their dining experience in the restaurant. The survey uses a scale of one to five, five being best to indicate customer satisfaction. Mel’s customer satisfaction averaged 2.5 last year, but this year it is 2.9. Is this difference statistically significant? ____
7. Sally’s Beauty Salon just opened for business. Sally assigns the stylists customers on a rotation basis so that everyone is kept busy all day. One month after she opened the salon, Sally’s customer count for each stylist was (a) 20 customers; (b) 30 customers; (c) 15 customers; and (d) 25 customers. Has Sally been fair in how she allocates customers to each of the stylists? ____
8. A comparison of salaries between male and female employees in the same organization. _P__
Click here to see answer by stanbon(26259) |
Question 173455: I am having difficulty with the following homework assignment. Could someone please check my answers and help? Thanks!
INSTRUCTIONS: Label each of the following situations “P” if it is an example of parametric data or “NP” if it is an example of nonparametric data.
1. A manufacturer produces a batch of memory chips (RAM) and measures the mean-time-between-failures (MTBF). The manufacturer then changes a manufacturing process and produces another batch and again measures the MTBF. Did the change to the process improve the MTBF? __P__
2. From a written survey where the respondents were asked to rate an individual on a scale of 1 to 5, one group rated an individual a 3.7, another group rated the individual a 4.3. Is the difference statistically significant? __NP__
3. A catering company is buying equipment in order to set up their own store. They have a choice of two ovens that they can purchase for the store. The used oven is $100 less than the new oven, but its heating calibration is off by 20 degrees. Which one is a better buy for them? __P__
4. Jim Smith owns three real estate offices in Anytown. He has decided to open one more office, but he cannot decide between Hometown or Uptown as the town where he wants to locate. He will be comparing the mean number of homes sold per real estate agent, and the mean commission percentage earned by agents in the two towns to make his decision. _P_
5. A study to determine if job absenteeism is distributed evenly over the week. _NP___
6. Mel’s Diner has been surveying their customers for the past couple of years about their dining experience in the restaurant. The survey uses a scale of one to five, five being best to indicate customer satisfaction. Mel’s customer satisfaction averaged 2.5 last year, but this year it is 2.9. Is this difference statistically significant? __NP__
7. Sally’s Beauty Salon just opened for business. Sally assigns the stylists customers on a rotation basis so that everyone is kept busy all day. One month after she opened the salon, Sally’s customer count for each stylist was (a) 20 customers; (b) 30 customers; (c) 15 customers; and (d) 25 customers. Has Sally been fair in how she allocates customers to each of the stylists? __P___
8. A comparison of salaries between male and female employees in the same organization. __P__
Click here to see answer by stanbon(26259) |
Question 172989: A) What is the 90% confidence interval for the variance of exam scores for 28 algebra students, if the standard deviation of their last exam was 12.7?
B)A lawyer researched the average number of years served by 49 different justices on the Supreme Court. The average number of years served was 14.9 years with a standard deviation of 8.6 years. What is the 95% confidence interval for the average number of years served by all Supreme Court justices?
C)A high school math teacher thinks the variance on his next math test should be 125. When his class of 27 students takes the next test, they have a standard deviation of 133. The test value for this data would be 27.664.
Click here to see answer by stanbon(26259) |
Question 173960: An exeriment to measure the effect of giving growth hormones to girls affected by Turner's Syndrome was carried out recently in Vancouver. All 34 girls in the study were given the growth hormone and their heights were measured at the time the hormone was given and again one year later. No measurements were made on their final adult heights. Which of the following is not a problem with this experiment:
(a) There was no blinding.
(b) There was no control group.
(c) Nonresponse bias.
(d) There was insufficient attentionto the placebo effect.
(e) Because final heights were not measured, it is impossible to tell if the hormone affected final height or only accelerated growth and made no difference to final height.
Click here to see answer by Alan3354(6059)  |
Question 174883: Suppose that a researcher is interested in estimating the mean systolic blood pressure, , of executives of major corporations. He plans to use the blood pressures of a random sample of executives of major corporations to estimate . Assuming that the standard deviation of the population of systolic blood pressures of executives of major corporations is mm Hg, what is the minimum sample size needed for the researcher to be confident that his estimate is within mm Hg of ?
Click here to see answer by stanbon(26259) |
Question 175302: In establishing warranties on HDTV sets, the manufacturer wants to set the limits so that few will need repair at manufacturer expense. On the other hand, the warranty period must be long enough to make the purchase attractive to the buyer. For a new HDTV the mean number of months until repairs are needed is 36.84 with a standard deviation of 3.34 months. Where should the warranty limits be set so that only 10 percent of the HDTVs need repairs at the manufacturer's expense?
Click here to see answer by stanbon(26259) |
Question 175479: Recently, students in a marketing research class were interested in the driving behavior of students. Specifically, the marketing students were interested if exceeding the speed limit was related to gender. They collected the following responses from 100 randomly selected students: Speeds Does not speed Males 40 25 Females 10 25
1. The appropriate test to analyze the relationship between gender and education is:
A. regression analysis
B. Analysis of variance
C. Contingency table analysis
D. Goodness-of-fit
2. The null hypothesis for the analysis is:
A. There is no relationship between gender and speeding.
B. The correlation between gender and speeding is zero.
C. As gender increases, speeding increases.
D. The mean of gender equals the mean of speeding.
3. The degrees of freedom for the analysis is:
A. 1
B. 2
C. 3
D. 4
4. Using 0.05 as the significance level, what is the critical value for the test statistic?
A. 9.488
B. 5.991
C. 7.815
D. 3.841
5. What is the value of the test statistic?
A. 100
B. 9.89
C. 50
D. 4.94
6. Based on the analysis, what can be concluded?
A. Gender and speeding are correlated.
B. Gender and speeding are not related.
C. Gender and speeding are related.
D. No conclusion is possible.
Click here to see answer by stanbon(26259) |
Question 175565This question is from textbook Applied Statistics in Business and Economics
: 10.52 One group of accounting students took a distance learning class, while another group took the same course in a traditional classroom. At α = .10, is there a significant difference in the mean scores listed below? (a) State the hypotheses. (b) State the decision rule and sketch it. (c) Find the test statistic. (d) Make a decision. (e) Use Excel to find the p-value and interpret it.
Exam Scores for Accounting Students
Statistic Distance Classroom
Mean scores ¯x1 = 9.1 ¯x2 = 10.3
Sample std. dev. s1 = 2.4 s2 = 2.5
Number of students n1 = 20 n2 = 20
This question is from textbook Applied Statistics in Business and Economics
Click here to see answer by stanbon(26259) |
Question 175509: 14. The following table shows the adjustment to civilian life and place of residence.
*SORRY.. this is the only way i could reformat the "table" for it to make sense. The actual table was not lining up.
(Residence After Release From Prison) Adjustment to Civilian Life = Outstanding
(Hometown) = 27
(Not hometown)= 13
Total = 40
(Residence After Release From Prison) Adjustment to Civilian Life = Good
(Hometown) = 35
(Not hometown)= 15
Total = 50
(Residence After Release From Prison) Adjustment to Civilian Life = Fair
(Hometown) = 33
(Not hometown)= 27
Total = 60
(Residence After Release From Prison) Adjustment to Civilian Life = Unsatisfactory
(Hometown) = 25
(Not hometown)= 25
Total = 50
What is the critical value for this contingency table at the 0.01 level of significance?
A) 9.488
B) 2.070
C) 11.345
D) 13.277
E) None of the above
Click here to see answer by stanbon(26259) |
Question 175517: The educational level and the social activity of a sample of executives follow.
Education Social Activity=Above Average
College = 30
High School = 20
Grade School = 10
Education Social Activity = Average
College = 20
High School = 40
Grade School = 50
Education Social Activity=Below Average
College = 10
High School = 90
Grade School = 130
What does the expected frequency for the "above average" social activity and "high school" education equal?
A) 9.50
B) 60.00
C) 22.50
D) 28.50
E) None of the above
Click here to see answer by stanbon(26259) |
Question 175483: A distributor of personal computers has five locations in the city. The sales in units for the first quarter of the year were as follows:
Location - Observed Sales (Units)
North Side - 70
Pleasantway - 75
Southwyck - 70
I-90 -50
Venice Avenue - 35
TOTAL = 300
What is the critical value at the 0.01 level of risk?
A) 7.779
B) 15.033
C) 13.277
D) 5.412
E) None of the above
Click here to see answer by stanbon(26259) |
Question 175638: 2. You will be asked to identify the type of variable (quantitative or qualitative) in each of the following situations.
a. Whether or not an individual would be willing to spend 10 percent more for energy from a non-polluting source.
b. The amount an individual user pays for internet access on a monthly basis.
I chose quantitative for both a and b. Is that correct?
Click here to see answer by vleith(1977) |
Question 175646: You will be asked to determine whether each of the following quantitative variables is discrete or continuous.
A.) The amount of money the CEO is paid.
B.) The number of staff members who report to the CEO.
For A.) I choose discrete and for B.) I chose continuous. Are they correct?
Click here to see answer by user_dude2008(715) |
Question 175661: Diana has a box containing 6 blue, 8 red, 5 purple, 9 green, and 2 clear marbles that are all the same size and shape. What is the probability of randomly choosing a clear marble on the first pick; replacing it, and then randomly choosing a purple marble on the second pick?
Click here to see answer by checkley75(3666) |
Question 175661: Diana has a box containing 6 blue, 8 red, 5 purple, 9 green, and 2 clear marbles that are all the same size and shape. What is the probability of randomly choosing a clear marble on the first pick; replacing it, and then randomly choosing a purple marble on the second pick?
Click here to see answer by jim_thompson5910(13787) |
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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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