Tutors Answer Your Questions about Probability-and-statistics (FREE)
Question 400439: How would you interpret the findings of a correlation study that reported a linear correlation coefficient of − 1.34?
The only thing I know is that it represents a negative correlation. Please shed any light you can.
Click here to see answer by robertb(5830)   |
Question 400430: Suppose there are 35 students in a class and 30 lectures in 1 semester. If 4 students are randomly picked in a class to answer questions, what is the probability that one student is never called during the semester?
I would say almost 0% but I don't know where to begin.
Click here to see answer by stanbon(75887) |
Question 400430: Suppose there are 35 students in a class and 30 lectures in 1 semester. If 4 students are randomly picked in a class to answer questions, what is the probability that one student is never called during the semester?
I would say almost 0% but I don't know where to begin.
Click here to see answer by robertb(5830) |
Question 400334: Please help me solve this problem.
The probabilities of ordering 0,1,2,3, or 4 toppings on a pizza are 2/10, 5/10, 2/10, 7/100, 3/100 respectively. What is the mathematical expectation for the number of toppings ordered on a pizza? (State the answer in integer/decimal form, i.e. 1.30, .35, etc.)
Click here to see answer by stanbon(75887) |
Question 400333: Please help me solve this problem.
How many different sums of money can be made from a set of coins consisting of a penny, a nickel, a dime, a quarter, a half-dollar, and a silver dollar if exactly 4 coins are used for each sum?
Click here to see answer by stanbon(75887) |
Question 400020: you have ten six-sided dice in a cup. If you shake the cup, toss all
of the dice on the table at one time, and count the number of threes, how many
threes would you expect to see?
What percentage of the time would you expect to see an outcome of five
threes?
Click here to see answer by stanbon(75887) |
Question 399760: We want to conduct a hypothesis test to see if a particular IQ assessment is calibrated
properly, meaning that people’s IQ according to the test is, on average, 100.
(a) What should our null hypothesis and our alternative hypothesis be?
(b) Explain what a type I error and a type II error would represent in terms of the IQ
assessment.
Click here to see answer by stanbon(75887) |
Question 400557: ____________________________
|category|easy|difficult|
|music||||0.2||0.15|
|sport||||0.2||0.1|
|history||0.1||0.05|
|nature|||0.15|0.05|
____________________________
(a) i am goint to take one card at random from the box.
what is the probability that it will be:
a history question? ......
an easy question? ......
(b) there are 40 cards in the box.
how many of these are music questions? ......
Click here to see answer by stanbon(75887) |
Question 400800: santa is working with 20 elves. he randomly selects the names of three different elves. the first paints the trains, the second elf paints all the dollhouses, and the third paints all the wooden blocks. in how many ways can santa assign these 20 elves to these three tasks?
Click here to see answer by checkley79(3341) |
Question 400989: The production manager at Bellevue Steel, a manufacturer of wheelchairs, wants to perform a second analysis of the number of defective wheelchairs produced on the day shift and afternoon shift. A sample of the production from 6 day shifts and 8 afternoon shifts revealed the following number of defects.
At the 0.10 significance level, is there a difference in the mean number of defects per shift?
Day 10 9 6 6 4 9
Afternoon 8 10 7 5 8 10 5 6
1. State the null and alternate hypotheses.
2. What is the decision rule?
3. What is the value of the test statistic?
4. What is your decision regarding the null hypothesis?
5. What is the p-value?
6. Interpret the result.
Click here to see answer by stanbon(75887) |
Question 401195: A light-bulb manufacturer claims that the light bulbs produced by his company have an average life of 1200 hours. A consumer agency wishes to test this claim, against the alternative of fraudulent (i.e. the alternative that average life span is less than 1200 hours). A random sample of 16 bulbs is chosen from production and tested as the life times. The summary statistics turn out to X=1148.5 hours and S^2=12544.224. Based on these summary statistics, and at the α=0.05 level of significance
a) Obtain a 100(1-α )% confidence interval for the population mean ( μ ).
b) Formulate the corresponding hypothesis and test it.
How do I do This?
Click here to see answer by stanbon(75887) |
Question 401245: Please help me in answering this question. In a standard normal distribution, what is the probability of randomly selecting a value between -2.555 and -0.745? Round to four decimal places.
Also 16. Determine the appropriate approach to conduct a hypothesis test for this claim: Fewer than 5% of patients experience negative treatment effects. Sample data: Of 500 randomly selected patients, 2.2% experience negative treatment effects.
A) Use the normal distribution.
B) Use the Student t distribution.
C) Use the chi-square distribution.
D) Use nonparametric or bootstrapping methods.
Thank you
Click here to see answer by stanbon(75887) |
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43111..43155, 43156..43200, 43201..43245, 43246..43290, 43291..43335, 43336..43380, 43381..43425, 43426..43470, 43471..43515, 43516..43560, 43561..43605, 43606..43650, 43651..43695, 43696..43740, 43741..43785, 43786..43830, 43831..43875, 43876..43920, 43921..43965, 43966..44010, 44011..44055, 44056..44100, 44101..44145, 44146..44190, 44191..44235, 44236..44280, 44281..44325, 44326..44370, 44371..44415, 44416..44460, 44461..44505, 44506..44550, 44551..44595, 44596..44640, 44641..44685, 44686..44730, 44731..44775, 44776..44820, 44821..44865, 44866..44910, 44911..44955, 44956..45000, 45001..45045, 45046..45090, 45091..45135, 45136..45180, 45181..45225, 45226..45270, 45271..45315, 45316..45360, 45361..45405, 45406..45450, 45451..45495, 45496..45540, 45541..45585, 45586..45630, 45631..45675, 45676..45720, 45721..45765, 45766..45810, 45811..45855, 45856..45900, 45901..45945, 45946..45990, 45991..46035, 46036..46080, 46081..46125, 46126..46170, 46171..46215, 46216..46260, 46261..46305, 46306..46350, 46351..46395, 46396..46440, 46441..46485, 46486..46530, 46531..46575, 46576..46620, 46621..46665, 46666..46710, 46711..46755, 46756..46800, 46801..46845, 46846..46890, 46891..46935, 46936..46980, 46981..47025, 47026..47070, 47071..47115, 47116..47160, 47161..47205, 47206..47250, 47251..47295, 47296..47340, 47341..47385, 47386..47430, 47431..47475, 47476..47520, 47521..47565, 47566..47610, 47611..47655, 47656..47700, 47701..47745, 47746..47790, 47791..47835, 47836..47880, 47881..47925, 47926..47970, 47971..48015, 48016..48060, 48061..48105, 48106..48150, 48151..48195, 48196..48240, 48241..48285, 48286..48330, 48331..48375, 48376..48420, 48421..48465, 48466..48510, 48511..48555, 48556..48600, 48601..48645, 48646..48690, 48691..48735, 48736..48780, 48781..48825, 48826..48870, 48871..48915, 48916..48960, 48961..49005, 49006..49050, 49051..49095, 49096..49140, 49141..49185, 49186..49230, 49231..49275, 49276..49320, 49321..49365, 49366..49410, 49411..49455, 49456..49500, 49501..49545, 49546..49590, 49591..49635, 49636..49680, 49681..49725, 49726..49770, 49771..49815, 49816..49860, 49861..49905, 49906..49950, 49951..49995, 49996..50040, 50041..50085, 50086..50130, 50131..50175, 50176..50220, 50221..50265, 50266..50310, 50311..50355, 50356..50400, 50401..50445, 50446..50490, 50491..50535, 50536..50580, 50581..50625, 50626..50670, 50671..50715, 50716..50760, 50761..50805, 50806..50850, 50851..50895, 50896..50940, 50941..50985, 50986..51030, 51031..51075, 51076..51120, 51121..51165, 51166..51210, 51211..51255, 51256..51300, 51301..51345
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