Tutors Answer Your Questions about Probability-and-statistics (FREE)
Question 384269: The last mid-term examination for math 125 has 100 multiple choice questions. Each question has five possible answers and only one is correct. Many of the students make random guesses for each problem.
i.) Find the mean and standard deviation for the number of correct answers for such student?
ii.) Would it be unusual for a student to pass the exam by guessing and getting at least 60 correct?
Click here to see answer by stanbon(57361)  |
Question 384288: I'm trying to figure out the following problem.
Assume the variable x is normally distributed with mean u=90 and standard deviation o=4 Find the indicated probability:
P(80 < x < 87)
I'm using a TI-83 Calculator & have entered the following information.
invNorm(.80,90,4)= 93.3665
invNorm(.87,90,4)= 94.5056
I'm not sure I'm solving correctly as the second solution should be smaller than 87. Right?
Click here to see answer by stanbon(57361) |
Question 384284: What is the procedure used to look up a certain value on a standardized normal distribution? What do these values represent?
I know to use the z score but I'm not sure why. Can anyone help me with this one please?
Click here to see answer by stanbon(57361) |
Question 384290: 1) What is the total area under the curve of a standardized normal distribution? How does the symmetric line of a standardized normal distribution affect the total area under the curve?
2) Please indicate an application of a normal distribution you have come across
Click here to see answer by stanbon(57361) |
Question 384295: Box A contains 6 red and 7 yellow balls while box B contains 5 red and 3 yellow balls. A box is chosen at random and a ball is selected from it. The probability of choosing box A is 58%. Find the the probability that the ball came from box A if the ball was yellow.
Click here to see answer by robertb(4012)  |
Question 384342: I would like to know if I answered this question correctly. I will not get the test back to know.
The probability of a flight being delayed at Lucky Lou Airport is .12 What is the probability that the next 3 flights will leave on time?
I answered .88 my thoughts were .12 is 12% and .88 is 88% and 88% + 12% = 100%
Can someone let me know if I answered this right?
Thank you so much!!
Click here to see answer by stanbon(57361) |
Question 384349: If you roll a pair of dice (expl. the game of craps (dice), and on your first roll the total is 6, what is the probability of rolling another 6 on the next roll of the dice? What are the probabilities of making a 6 on each roll thereafter?
Thank you for your consideration and response. My email is hd@glennhill.com
HD
Click here to see answer by stanbon(57361) |
Question 384379: I know this does not have to do with algebra but I have no where else to turn! Just a simple statistics question. If you know the chi square test statistic, the degrees of freedom, and the critical value how do you calculate the p- value without a calculator looking at the chi square distribution table? Assuming the standard deviation is .1, n=10, and the test statistic is 18.585. I know you have to look at the table and subtract n-1 to get degrees if freedom but I have no idea how to calculate an exact p- value without a calculator!!!
Click here to see answer by jim_thompson5910(28595) |
Question 384392: the probability that an american dies citizen in his 20th year is 0.00178 assume that a life insurence company will sell a 1000$ one year policy to a 19 year old for 5$ what is expected gain obtained by insurence company from selling one such polecy
Click here to see answer by stanbon(57361) |
Question 384378: The mean diameter of a CD disc is 12.0 cm, produced by a company called "Cardinal Best Compact Disk", with a standard deviation of 0.012. CD's that are more than one standard deviation from the mean cannot be shipped. How can a quality control engineer use these statistics to help the company produce CD's that can be shipped?
Click here to see answer by robertb(4012) |
Question 384393: 1. In a certain class, the average weight of girls is 10 kg less than the average weight of all the students, and the average weight of boys is 5 kg more than the average weight of all the students. What percent of the students in the class are girls?
(A) 20% (B) 25% (C) 33.33% (D) 35% (E) 40%
2. At a soccer match, the contractor provided dinner for 24 players, and fixed the price per person so as to gain 12.5% on his total outlay. However, 3 of the players were absent and the remaining 21 players paid the fixed price for their dinner and as such the contractor lost $1 on his total outlay. What was the charge of the dinner per person?
(A) $3 (B) $3.5 (C) $4.0 (D) $5 (E) $ 6
Click here to see answer by stanbon(57361) |
Question 384272: A team of biologist has been studying the childrens fishing pond in Fall-River. Let x represent the length of a single tilapia taken at random from the fishing pond. This group of the biologists has determined that x has a normal distution with mean u equals 10.2 inches and standard deviation o equals 1.4 inches.
i.) what is the porbability that a single tilapia selected at random from the pond is between 8 and 12 inches long?
ii.) what is the probability that the mean length x (bar) of five tilapia taken from at random from the pond is between 8 and 12 inches?
iii.) Is the result in parts a and b the same of different?
Click here to see answer by stanbon(57361) |
Question 384421: 8 students are confined in a room for 30 days with no sunlight. At the end of the experiment their cycle change to 25, 27, 25, 23, 24, 25, 26, and 25. What can you conclude about the 24 hour cycle? Use the steps of hypothesis testing and sketch the distributions involved.
This is my hard question can you please help me? Thanks for you time!
Click here to see answer by stanbon(57361) |
Question 384420: 8 students are confined in a room for 30 days with no sunlight. At the end of the experiment their cycle change to 25, 27, 25, 23, 24, 25, 26, and 25. What can you conclude? Use the steps of hypothesis testing and sketch the distributions involved.
This is my hard question can you please help me? Thanks for you time!
Click here to see answer by stanbon(57361) |
Question 384476: Suppose another box has resitors diistributed accourding to the Gaussion distribution, with a mean of 100Ω and a standard deviation of 2Ω. What is the probability that a resistor, selected at random from a box, will have a resistance greater than 101Ω?
Click here to see answer by stanbon(57361) |
Question 384377: You have just entered the real estate market in your area. The first eight homes you sold and their prices are given in the table below. Calculate the average selling price and the standard deviation.
Number of homes Selling Price
1 $340,000
2 $260,000
2 $280,000
3 $300,000
Click here to see answer by mtmorro(23)  |
Question 384519: A company that makes shampoo wants to test whether the average amount of shampoo per bottle is 16 ounces. The standard deviation is known to be 0.20 ounces. Assuming that the hypothesis test is to be performed using 0.10 level of significance and a random sample of n = 64 bottles, which of the following would be the correct formulation of the null and alternative hypotheses?
Answer
a.Ho : x-bar = 16HA : x-bar not equal to 16
Ho : u = 16HA : u not equal to 16
Ho : u >16HA : u < 16
Ho : x-bar > 16HA : x-bar <16
Click here to see answer by jim_thompson5910(28595) |
Question 384596: A person is picked at random from the group of l00 blood donors, broken down by blood type and gender as follows:
Male =blood type A is 20. type b is 8, type AB is l6, type O is 11
Female =blood type A is l5, type B is 6, type AB is l0, type O is l4
(a) What is the probability that the person selected is a FEMALE?
(b) What is the probability that the person selected has blood type O?
(c) Given that the person selected is a MALE, what is the probability that their blood type is AB?
(d) Given that the person's blood type is A, what is the probability that the person is a FEMALE/
(e) What is the probability that the person selected has blood type B or is a male?
(b)
Click here to see answer by stanbon(57361) |
Question 384654: show all work.....................
a disc jockey has 7 songs to play. five are slow songs, and two are fast songs. each song is to be played only once. in how many ways can the disc jockey play 7 songs if
the song can be played in any oder
the first song must be a slow song and the last song must be a slow song
the first two songs must be fast songs
Click here to see answer by edjones(7569)  |
Question 384685: a cyclist passes mile post 148 at 11:02 and passes mile post 134 T 11:26. Assuming the cyclist continues at the same speed, at what time does the cyclist pass mile post 106?
I had tried to work out this problem and cane up with the answer 48 minutes. is this correct?
Thank you for your time! I really appreciate the help!
Click here to see answer by mananth(12270)  |
Question 384760: In a distribution of scores with a mean of 35 and a standard deviation of 4, which event is more likely: that a randomly selected score will be between 29 and 31 or a randomly selected score will be between 40 and 42?
Click here to see answer by stanbon(57361) |
Question 384749: A test is composed of six multiple choice questions where each question has 4 choices. If the answer choices for each question are equally likely, find the probability of answering 3 OR 4 questions correctly
Click here to see answer by stanbon(57361) |
Question 384866: in the regression equation what does the letter "a" stand for and what does the letter "b" stand for?
a) y intercept
b)slope of the line
c)any value of the independent variable that is selected
d)none of the above
what is the variable used to predict another variable called?
a)independent
b)dependent
c)important
d)significant
e)none of the above
if all the plots on a scatter diagram lie on a straight line, what is the standard error of estimate?
a)-1
b)+1
c)0
d)infinity
e)none of the above
Click here to see answer by rfer(12660) |
Question 385027: suppose you have a 9 questions multiple choice test with 3 possible answers. also suppose you guess on each question. what would the probability of 0, 1, 2, 3,4,5,6,7,8,9, would be?? round four decimals places
Click here to see answer by stanbon(57361) |
Question 385047: Given a level of confidence of 95% and a population standard deviation of 9, answer:
A). What other information is necessary to find the sample size of (n)?
B). Find the Maximum Error of Estimate (E) if n = 56. Show all calculations.
**I did not do that well on a test. Can someone please help me to understand this?
Click here to see answer by stanbon(57361) |
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