Tutors Answer Your Questions about Probability-and-statistics (FREE)
Question 368895: A box contains 5 pennies, 5 dimes, 1 quarter, and 1 half dollar. You reach into the box (without looking) and select a single coin.
Identify the random variable. X =
Construct a probability distribution for this data.
Click here to see answer by robertb(4012)  |
Question 368830: In a group of 12 persons, 3 are left‐handed. Suppose that 2 persons are randomly selected from this group. Let x denote
the number of left‐handed persons in this sample. Write the probability distribution of x. You may draw a tree diagram
and use it to write the probability distribution.
Click here to see answer by robertb(4012)  |
Question 368889: You believe that there is a 20% chance that you will earn an A in your English class, a 10% chance that you will earn an A in your Physics class, and a 5% chance that you will earn an A in both classes.
Also, is this disjoint or independent?
Click here to see answer by robertb(4012)  |
Question 367797: You have two different teams of service technicians for two large
hospitals that are about the same age with the same types of equipment.
Recently you took data to determine the average repair time per the 2
separate groups. Analyze the data at the 0.05 alpha level 1 tail test
to determine if there is any difference between the 2 groups (times are
min.)
Group1: sample mean= 45.1 sample std deviation= 7.7 sample size = 30
Group2: sample mean= 57.1 sample std deviation= 2.4 sample size = 32
Click here to see answer by pfrazier(1) |
Question 369017: Describe what a type I and type II error would be for each of the following null hypotheses:
Ho: There is no difference in statistics texts.
Write a correct null and alternative hypothesis that tests the claim that the mean distance a student commutes to campus is no less than 8.2 miles.
Click here to see answer by ewatrrr(10682)  |
Question 369109: The theoretical probability of undesirable side effects resulting from taking Grebex is 1 in 20. If 100 people take Grebex to lower their blood pressure, how many will encounter undesirable side effects?
Click here to see answer by neatmath(300)  |
Question 369113: 9.76 A certain brand of flat white interior latex paint claims one-coat coverage of 400 square feet per
gallon. The standard deviation is known to be 20. A sample of 16 gallons is tested. (a) At α = .05
in a left-sided test, find the β risk and power assuming that the true mean is really 380 square feet
per gallon. (b) Construct a left-sided power curve, using increments of 5 square feet (400, 395,
390, 385, 380).
Click here to see answer by bioshockgrl(2) |
Question 369083: (1). Determine the critical region and critical values for z that would be used to test the null hypothesis at the given level of significance, as described in each of the following:
(A) Ho:u >/_81 and,Ha:u<81, a = 0.05
(> with line under)
(B) Ho:u= 45 and Ha:u (=/)45, a = 0.10
(C)Ho:u and Ha:u > 88, a = 0.01
(< with line under)
Click here to see answer by ewatrrr(10682)  |
Question 369145: A new drug can cause two unwanted sife effects: Drowsiness and headache. 6% of its users experienced drowsiness, 4% experienced headache, and 2% experienced both. What is the percentage of users who experienced neither side effect?
Click here to see answer by stanbon(57977) |
Question 369128: A clinical trial is conducted to compare an expetimental medication to placebo to reduce the symptoms of asthma. Two hundred participants are enrolled in the study and randomized to reveive either the experimental medication or placebo. The primary outcome is self-reported reduction of symptoms. Among 100 participants who received the experimental medication, 38 reported a reduction of symptoms aws compared to 21 participants of 100 assigned to placebo. Test if there is a significant difference in the proportions of participants reporting a reduction of symptoms between the wxperimental and placebo groups. Use a 5% level of significance. Run the test using the five-step approach In computing this fully discuss the hypothesis 5 step approach and any difficulties in computing it and the problems experienced.
Click here to see answer by stanbon(57977) |
Question 369381: If three digits are randomly selected, find the probability of getting at least one 7. Digits can be used more than once.
I tried doing the probability of not getting a 7 in each area:
P(not 7)= (.9)*(.9)*(.9)=.729
P(at least one 7)= 1-.729= .271
Is that right?
Click here to see answer by Alan3354(31532)  |
Question 369440: (N,V,S,A,N,T,A,R,A )
DIAGRAM 1
Base the diagram,some of the card label Y are put in a box.If a card is picked at random, probability of pickeing a Y card is 0.2, calculate the Y cards.
Click here to see answer by Fombitz(13828)  |
Question 369539: Ava is taking a multiple choice quiz for which she has not studied. There are 5 questions on the quiz and each question has four possible choices. If Ava guesses on each of the questions, what is the probability that she will receive a perfect score?
Click here to see answer by ewatrrr(10682)  |
Question 369654: Enrollment statistics at a certain college show that 55% of all students are men, 18% of the student body consists of women majoring in business, and 40% of all students major in business. A student is selected at random.
Find the conditional probability that the person majors in business if we are certain the person is a woman.
I've got P(men) = 55 and P(women majoring in business) = 18, but the 40% I do not know what to do. I tried Venn diagram and:
P(M U W) = P(M) + P(W) - P(M n W) I still cannot get answer..
Click here to see answer by edjones(7569)  |
Question 369654: Enrollment statistics at a certain college show that 55% of all students are men, 18% of the student body consists of women majoring in business, and 40% of all students major in business. A student is selected at random.
Find the conditional probability that the person majors in business if we are certain the person is a woman.
I've got P(men) = 55 and P(women majoring in business) = 18, but the 40% I do not know what to do. I tried Venn diagram and:
P(M U W) = P(M) + P(W) - P(M n W) I still cannot get answer..
Click here to see answer by jrfrunner(365)  |
Question 369692: In a survey of 150 seniors executives, 47% said that most common job interview mistake is to have little or no knowledge of the company. I need help with part B
a) If 6 of those surveyed executives are randomly selected without replacement for a follow-up survey, find the probability ... b) If part (a) is changed so that 9 of the surveyed executives are to be randomly selected without replacement, explain why the binomial probability formula cannot be used.
Click here to see answer by edjones(7569)  |
Question 369664: a recent article in vitality magazine reported that the mean amount of leisure time per week for american men is 40.0 hours. You believe this figure is too large and decide to conduct your own test. In a random sample of 60 men, you find that the mean is 37.8 hours of leisure per week and that the standard deviation of the sample is 12.2 hours. can you conclude that the information in the article is untrue? Use the .05 significance level. determine the p-value and explain its meaning.
Click here to see answer by stanbon(57977) |
Question 369661: How do you solve:
A children's theater found in a random survey that 65 customers bought one snack bar item, 40 bought two items, 26 bought three items, 14 bought four items, and 18 avoided the snack bar altogether. Use this information to find the expected number of snack bar items per customer.
Thank you!
Click here to see answer by stanbon(57977) |
Question 369802: concern 2-card hands from a standard 52-card deck.. A standard deck has13 cards from each of 4 suits (clubs, diamonds, hearts, spades). The 13 cards have face value 2 through10, jack, queen, king, or ace. Each face value is a "kind" of card. The jack, queen, and king are "face cards."
20. What is the probability that exactly one card is a spade?
21. What is the probability that at least one card is a spade?
22. What is the probability that both cards are face cards?
23. What is the probability that both cards are spade face cards?
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a student takes a True/False quiz with 4 questions, each equally likely to be either T or F.
50. What is the probability of getting the first two questions correct?
52. What is the probability of getting all four questions correct given that the answers to the first two questions are correct?
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64. A directory on a computer's hard disk contains 12 files, 3 of which have viruses. If a file with a virus is selected, the virus is detected and another file is then selected. Find the expected number of files that must be selected before a virus-free file is found
Click here to see answer by jrfrunner(365)  |
Question 369843: 11 Right Handed Girls
10 Right Handed Boys
2 Left Handed Girls
3 Left Handed Boys
A girl and a boy are chosen at random. What is the probability of picking a right-handed girl and a left-handed boy?
A) 20/676
B) 33/676
C) 20/169
D) 33/169
Click here to see answer by stanbon(57977) |
Question 369821: How do you solve:
In one version of the game keno, the house has a pot containing 80 balls, numbered 1 through 80. A player buys a ticket for $1 and marks one number on it (from 1 to 80). The house then selects 20 of the 80 numbers at random. If the number selected by the player is among the 20 selected by the management, the player is paid $3.20. Find the expected net winnings for this game.
Thank you!
Click here to see answer by robertb(4012)  |
Question 369908: The probability that robien hits the target is 0.6. The probability that John hits the target os 0.3. the probabilidity that Robin hits the target and John does not hit the target is:
Thank You, I appreciate it!
Click here to see answer by stanbon(57977) |
Question 369928: There are five peolpe in a room, three men and two women. They leave the room one by one, in random order, until the room is empty. What is the probability that:
a)The first person to leave the room is a woman.
b)The firs three people to leave the room are all men.
Thank You for your help, I appreciate it!
Click here to see answer by stanbon(57977) |
Question 369923: A computer prints out three digits chosen at random from 0 to 9, inclusive. Find the probability that:
a) All three digits are different.
b) The third digit differs from the first two digits.
Thank yoy very much for your answer!
Click here to see answer by edjones(7569)  |
Question 369889: can you help me with this exercise please
the probability that alysha will miss school today is 0.15
the probability that Carla will miss school today is 0.07
the probability that both of these student will not miss school today is?
I did it and I got this >> (0.85)(0.93)= 0.7905
Can someone tell me if this is right?!
Thank You!
Click here to see answer by robertb(4012)  |
Question 369966: Three boxess contain marbles,
first box, 3 red and 5 blue.
second box, 2 red and 4 yellow.
third box, 4 red and 2 blue.
a) Find the probability that a person selected a red marble.
b) Find the probability that a person selected a red marble, given that the person did not select the third box.
Thank you for your time and help. I really appreciate it.
Click here to see answer by robertb(4012)  |
Question 369915: The serial number on a $10 bill contains eight non-zero digits. If your $10 bill contains the digit 7 at least once, you win a prize. The probability that your $10 bill will be a prize-winning bill is:
Thank you very much!
Click here to see answer by robertb(4012)  |
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