Tutors Answer Your Questions about Probability-and-statistics (FREE)
Question 145821: The names of three potential presidential candidates, Smith, Jones and Green, were presented to a focus group to determine the preferences of voters. The null hypothesis would be:
A) There is no preference among the candidates
B) There are definite preferences among the candidates
C) Green is preferred over the other two
D) More degrees of freedom are required
E) This cannot be determined without more information
Click here to see answer by stanbon(57290)  |
Question 145859: Please, help me with these questions, Thanks.
1. Nancy Giggles has not been doing well on statistics examinations. She decides to sample 12 of her friends to determine the number of hours spent studying for Test 3 and the score out of 100 received on that test. The results:
Test 4 Score
Hours of study
47
7
55
10
87
39
98
43
37
2
71
12
100
51
98
48
85
23
82
26
56
7
78
14
(i) Find the equation of the regression line using the least square technique. Interpret the meanings conveyed by the regression equation.
(ii) Compute the correlation coefficient and the coefficient of Determination. Interpret these values.
2. David Gallano, a wine merchant, has selected opinions on grape wine quality from a random sample of his customers. The customers tasted wine made from grapes grown in three regions of the country. The customers rated wine quality on a scale of 1 (best) to 4 (worst). The sample data looks like:
Customer Quality Rating of Wine by Grape-growing region
Quality Rating
Growing Region
I
Growing Region
II Growing Region
III
Row Total
1
15
10
6
31
2
7
13
12
32
3
11
12
8
31
4
3
8
15
26
Column Total
36
43
41
120
David wants to know whether quality ratings are independent of the grape-growing region. Can you conclude at a 95% confidence that the quality rating is independent of the growing region?
Click here to see answer by stanbon(57290) |
Question 145867: What are the assumptions for using ANOVA?
A) The sampled populations follow the normal distribution.
B) The populations have equal standard deviations.
C) The samples are randomly selected and are independent
D) None of the above
E) All of the above
Click here to see answer by stanbon(57290) |
Question 145946: I do not have an isbn number it is not a textbook, sorry!
A pair of dice is rolled, what are the odds of each of the following
A)A sum of seven
b) a sum of 11
c) a sum of 7 or a 11 turning up
d) a sum of 2 or a sum of 12 turning
e) a sum greater than 9 turning up is
Thankyou
Click here to see answer by stanbon(57290) |
Question 145924: 4. Which of the following statements is true?
a. As the standard deviation of the population increases, the standard error of the mean increases.
b. As the standard deviation of the population increases, the mean of the sampling distribution of means increases.
c. As the population mean increases, the mean of the sampling distribution of means decreases.
d. As the sample size increases, the standard error of the mean increases.
Click here to see answer by vleith(2825) |
Question 145932: Which of the following does NOT hold true for the t distribution?
A) Confidence intervals will be wider than for large samples.
B) The region of acceptance will be larger than for large samples.
C) A larger computed t value will be needed to reject the null hypothesis than for large samples using z.
D) There is only one t distribution.
E) None of the above.
Click here to see answer by stanbon(57290) |
Question 145926: 6. For any given level of a, a confidence interval that is constructed using the t distribution will utilize a t value corresponding to an area of _________ in the tails of the distribution.
a. 2a
b. a
c. a/2
d. a/4
Click here to see answer by stanbon(57290) |
Question 146016:
Can’t cook 750
No time to cook 115
Can’t take food on the go 87
High cost 58
Poor taste 43
Hard to find 28
Confusion about nutrition 13
Use the above chart, which shows the results of a survey in which 1094 adults were asked why they don’t always eat healthy food. Find the probability of randomly selecting an adult from the sample who feels that healthy foods have high cost OR are hard to find. ___________________
Click here to see answer by stanbon(57290) |
Question 146015: Saturday you wash and dry 9 pair of pants you have 4 blue jeans, 2 khakis and 3 black. You close your eyes and randomly pick a pair out of the dryer, what is the probability that you will first select and remove a black pair, AND then you select a pair of blue jeans? ________________
Click here to see answer by stanbon(57290) |
Question 146014: The table shows the results of a survey in which 142 men and 145 women workers ages 25 to 64 were asked if they have at least one month’s income set aside for emergencies.
Men Women Total
Less than one month’s income 66 83 149
One month’s income or more 76 62 138
Total 142 145 287
Find the probability that a randomly selected worker has one month’s income or more set aside for emergencies. ____________
Given that a randomly selected worker is male, find the probability that the worker has less than one month’s income. ____________
Click here to see answer by stanbon(57290) |
Question 145930: What does the appropriate use of the t distribution for hypothesis testing assume about the population?
A) Near normal in shape
B) Standard deviation is known
C) Positively skewed
D) Standard deviation is unknown
E) Both “a” and “d” are correct
Click here to see answer by nabla(475) |
Question 146066: Do a larger proportion of college students than young children eat cereal? Researchers surveyed both age groups to find the answer. The results are shown in the table below. (a) State the hypotheses used to answer the question. (b) Using α = .05, state the decision rule and sketch it. (c) Find the sample proportions and z statistic. (d) Make a decision. (e) Find the p-value and interpret it. (f) Is the normality assumption fulfilled? Explain
Statistic College Students (ages 18–25) Young Children (ages 6–11)
Number who eat cereal x1 = 833 x2 = 692
Number surveyed n1 = 850 n2 = 740
Click here to see answer by stanbon(57290) |
Question 146065: Has the cost to outsource a standard employee background check changed from 2005 to 2006? A random sample of 10 companies in spring 2005 showed a sample average of $105 with a sample standard deviation equal to $32. A random sample of 10 different companies in spring 2006 resulted in a sample average of $75 with a sample standard deviation equal to $45. (a) Conduct a hypothesis test to test the difference in sample means with a level of significance equal to .05. Assume the population variances are not equal. (b) Discuss why a paired sample design might have made more sense in this case.
Click here to see answer by stanbon(57290) |
Question 146099: how would i do this? A box of 6 coins (penny, nickel, dime or quarter) worth $0.67 is shaken. What is the probability that a nickel is drawn first and then a quarter? Assume no replacement and that all coins are equally likely.
Click here to see answer by vleith(2825) |
Question 146112: Test at the 0.01 level the statement that 55% of those families who plan to purchase a vacation residence in Florida want a condominium. The null hypothesis is = 0.55 and the alternate is is not equal to 0.55. A random sample of 400 families who planned to buy a vacation residence revealed that 228 families want a condominium. What decision should be made regarding the null hypothesis?
Click here to see answer by stanbon(57290) |
Question 146159: A cognitive retraining clinic assists outpatient victims of head injury, anoxia, or other conditions
that result in cognitive impairment. Each incoming patient is evaluated to establish an appropriate
treatment program and estimated length of stay. To see if the evaluation teams are consistent,
12 randomly chosen patients are separately evaluated by two expert teams (A and B) as shown. At
the .10 level of significance, are the evaluator teams consistent in their estimates? State your
hypotheses and show all steps clearly.
Estimated Length of Stay in Weeks
Patient
Team 1 2 3 4 5 6 7 8 9 10 11 12
A 24 24 52 30 40 30 18 30 18 40 24 12
B 24 20 52 36 36 36 24 36 16 52 24 16
Click here to see answer by stanbon(57290) |
Question 146161: Please can someone Take a look at Problems 145964, 145965, 145966, 145967, 145968, 145969, and 145970-74? I posted these on friday and I really do need help with these as soon as conveniently possible. Thanks.
Click here to see answer by stanbon(57290) |
Question 146432: A personnel manager is concerned about absenteeism. She decides to sample the records to determine if absenteeism is distributed evenly throughout the six-day workweek. The null hypothesis to be tested is: Absenteeism is distributed evenly throughout the week. The 0.01 level is to be used. The sample results are:
Day of the Week Number Absent
Monday 12
Tuesday 9
Wednesday 11
Thursday 10
Friday 9
Saturday 9
7. What is the expected frequency?
A. 9
B. 10
C. 11
D. 12
8. What is the calculated value of chi-square?
A. 1.0
B. 0.5
C. 0.8
D. 8.0
9. What is your conclusion?
A. Absenteeism is evenly distributed throughout the week.
B. Absenteeism is not evenly distributed throughout the week.
C. I cannot say anything about absenteeism based on my statistics.
D. Absenteeism is increasing throughout the week.
Click here to see answer by stanbon(57290) |
Question 146436: Which of the following are true statements about the chi-square distribution?
A) Distribution is negatively skewed
B) Chi-square is based on two sets of degrees of freedom, one for the numerator and one for the denominator
C) Its shape is based on the degrees of freedom
D) All of the above are true
E) None of the above are true
Click here to see answer by stanbon(57290) |
Question 146435: 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
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
13. To analyze data cross-classified in a contingency table, how are the degrees of freedom found?
A) N-1
B) Rows - Columns
C) (Rows) x (Columns)
D) (Rows - 1) x (Columns - 1)
E) None of the above
14. The following table shows the adjustment to civilian life and place of residence.
Residence After Adjustment to Civilian Life
Release From Prison Outstanding Good Fair Unsatisfactory
Hometown 27 35 33 25
Not hometown 13 15 27 25
Total 40 50 60 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
15. The educational level and the social activity of a sample of executives follow.
Social Activity
Education Above Average Average Below Average
College 30 20 10
High School 20 40 90
Grade School 10 50 130
What does the expected frequency for the "above average" social activity and "high school" education equal?
A) 9.50 D) 28.50
B) 60.00 E) None of the above
C) 22.50
Click here to see answer by stanbon(57290) |
Question 146434: Two chi-square distributions were plotted on the same chart. One distribution was for 3 degrees of freedom and the other was for 12 degrees of freedom. Which distribution would tend to approach a normal distribution?
A)3 degrees
B) 12 degrees
C) 15 degrees
D) All would
E) None of the above
Click here to see answer by stanbon(57290) |
Question 146428: In a three-digit lottery, each of the three digits is supposed to have the same probability of occurrence
(counting initial blanks as zeros, e.g., 32 is treated as 032). The table shows the frequency
of occurrence of each digit for 90 consecutive daily three-digit drawings. (a) Make a bar chart and
describe it. (b) Calculate expected frequencies for each class. (c) Perform the chi-square test for a
uniform distribution. At α = .05, can you reject the hypothesis that the digits are from a uniform
population? Lottery3
Digit Frequency
0 33
1 17
2 25
3 30
4 31
5 28
6 24
7 25
8 32
9 25
Total 270
Click here to see answer by stanbon(57290) |
Question 146430: 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(57290) |
Question 146423: A certain airplane has two independent alternators to provide electrical power. The probability that a given alternator will fail on a 1-hour flight is .02. What is that (a) both will fail (b) Neither will fail? (c) One or the other will fail? Show all steps carefully?
Click here to see answer by stanbon(57290) |
Question 147139: The probability that San Franciso plays in the next Super Bowl is nine times the probability that they do not play in the next Super Bowl. The propability that San Francisco plays in the next Super Bowl plus the probability that they do not play is 1. What is the probability that San francisco plays in the next Super Bowl?
Click here to see answer by mangopeeler07(462) |
Question 147378: Alan is jealous that his neighbor down the street has a very cool toy that he has been admiring for 20 years now. He decides to break in and steal it. He knows that the house is monitored by a security system that requires a 5digit pass code. He knows that it needs 2 digits and 3 letters. How many pass keys are there if no digits can be repeated?
Click here to see answer by vleith(2825) |
Question 147463: an auditor reviewed 25 oral surgery insurance claims form a particular surgical office, determining that the mean out-of-pocket patient billing above the reimbused 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(57290) |
|
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, 4861..4905, 4906..4950, 4951..4995, 4996..5040, 5041..5085, 5086..5130, 5131..5175, 5176..5220, 5221..5265, 5266..5310, 5311..5355, 5356..5400, 5401..5445, 5446..5490, 5491..5535, 5536..5580, 5581..5625, 5626..5670, 5671..5715, 5716..5760, 5761..5805, 5806..5850, 5851..5895, 5896..5940, 5941..5985, 5986..6030, 6031..6075, 6076..6120, 6121..6165, 6166..6210, 6211..6255, 6256..6300, 6301..6345, 6346..6390, 6391..6435, 6436..6480, 6481..6525, 6526..6570, 6571..6615, 6616..6660, 6661..6705, 6706..6750, 6751..6795, 6796..6840, 6841..6885, 6886..6930, 6931..6975, 6976..7020, 7021..7065, 7066..7110, 7111..7155, 7156..7200, 7201..7245, 7246..7290, 7291..7335, 7336..7380, 7381..7425, 7426..7470, 7471..7515, 7516..7560, 7561..7605, 7606..7650, 7651..7695, 7696..7740, 7741..7785, 7786..7830, 7831..7875, 7876..7920, 7921..7965, 7966..8010, 8011..8055, 8056..8100, 8101..8145, 8146..8190, 8191..8235, 8236..8280, 8281..8325, 8326..8370, 8371..8415, 8416..8460, 8461..8505, 8506..8550, 8551..8595, 8596..8640, 8641..8685, 8686..8730, 8731..8775, 8776..8820, 8821..8865, 8866..8910, 8911..8955, 8956..9000, 9001..9045, 9046..9090, 9091..9135, 9136..9180, 9181..9225, 9226..9270, 9271..9315, 9316..9360, 9361..9405, 9406..9450, 9451..9495, 9496..9540, 9541..9585, 9586..9630, 9631..9675, 9676..9720, 9721..9765, 9766..9810, 9811..9855, 9856..9900, 9901..9945, 9946..9990, 9991..10035, 10036..10080, 10081..10125, 10126..10170, 10171..10215, 10216..10260, 10261..10305, 10306..10350, 10351..10395, 10396..10440, 10441..10485, 10486..10530, 10531..10575, 10576..10620, 10621..10665, 10666..10710, 10711..10755, 10756..10800, 10801..10845, 10846..10890, 10891..10935, 10936..10980, 10981..11025, 11026..11070, 11071..11115, 11116..11160, 11161..11205, 11206..11250, 11251..11295, 11296..11340, 11341..11385, 11386..11430, 11431..11475, 11476..11520, 11521..11565, 11566..11610, 11611..11655, 11656..11700, 11701..11745, 11746..11790, 11791..11835, 11836..11880, 11881..11925, 11926..11970, 11971..12015, 12016..12060, 12061..12105, 12106..12150, 12151..12195, 12196..12240, 12241..12285, 12286..12330, 12331..12375, 12376..12420, 12421..12465, 12466..12510, 12511..12555, 12556..12600, 12601..12645, 12646..12690, 12691..12735, 12736..12780, 12781..12825, 12826..12870, 12871..12915, 12916..12960, 12961..13005, 13006..13050, 13051..13095, 13096..13140, 13141..13185, 13186..13230, 13231..13275, 13276..13320, 13321..13365, 13366..13410, 13411..13455, 13456..13500, 13501..13545, 13546..13590, 13591..13635, 13636..13680, 13681..13725, 13726..13770, 13771..13815, 13816..13860, 13861..13905, 13906..13950, 13951..13995, 13996..14040, 14041..14085, 14086..14130, 14131..14175, 14176..14220, 14221..14265, 14266..14310, 14311..14355, 14356..14400, 14401..14445, 14446..14490, 14491..14535, 14536..14580, 14581..14625, 14626..14670, 14671..14715, 14716..14760, 14761..14805, 14806..14850, 14851..14895, 14896..14940, 14941..14985, 14986..15030, 15031..15075, 15076..15120, 15121..15165, 15166..15210, 15211..15255, 15256..15300, 15301..15345, 15346..15390, 15391..15435, 15436..15480, 15481..15525, 15526..15570, 15571..15615, 15616..15660, 15661..15705, 15706..15750, 15751..15795, 15796..15840, 15841..15885, 15886..15930, 15931..15975, 15976..16020, 16021..16065, 16066..16110, 16111..16155, 16156..16200, 16201..16245, 16246..16290, 16291..16335, 16336..16380, 16381..16425, 16426..16470, 16471..16515, 16516..16560, 16561..16605, 16606..16650, 16651..16695, 16696..16740, 16741..16785, 16786..16830, 16831..16875, 16876..16920, 16921..16965, 16966..17010, 17011..17055, 17056..17100, 17101..17145, 17146..17190, 17191..17235, 17236..17280, 17281..17325, 17326..17370, 17371..17415, 17416..17460, 17461..17505, 17506..17550, 17551..17595, 17596..17640, 17641..17685, 17686..17730, 17731..17775, 17776..17820, 17821..17865, 17866..17910, 17911..17955, 17956..18000, 18001..18045, 18046..18090, 18091..18135, 18136..18180, 18181..18225, 18226..18270, 18271..18315, 18316..18360, 18361..18405, 18406..18450, 18451..18495, 18496..18540, 18541..18585, 18586..18630, 18631..18675, 18676..18720, 18721..18765, 18766..18810, 18811..18855, 18856..18900, 18901..18945, 18946..18990, 18991..19035, 19036..19080, 19081..19125, 19126..19170, 19171..19215, 19216..19260, 19261..19305, 19306..19350, 19351..19395, 19396..19440, 19441..19485, 19486..19530, 19531..19575, 19576..19620, 19621..19665, 19666..19710, 19711..19755, 19756..19800, 19801..19845, 19846..19890, 19891..19935, 19936..19980, 19981..20025, 20026..20070, 20071..20115, 20116..20160, 20161..20205, 20206..20250, 20251..20295, 20296..20340, 20341..20385, 20386..20430, 20431..20475, 20476..20520, 20521..20565, 20566..20610, 20611..20655, 20656..20700, 20701..20745, 20746..20790, 20791..20835, 20836..20880, 20881..20925, 20926..20970, 20971..21015, 21016..21060, 21061..21105, 21106..21150, 21151..21195, 21196..21240
|
