Questions on Algebra: Probability and statistics answered by real tutors!

Tutors Answer Your Questions about Probability-and-statistics (FREE)

Question 428028: In a certain large city the proportion of people without a vehicle is twice that of those with one vehicle. The proportion with one vehicle is twice that of those with two vehicles. The proportion with two vehicles is equal to that for those who own three or more vehicles. If a person is selected at random from that population, what is the probability that person will own exactly one vehicle?
I don't know how to wrap my head around this.
Click here to see answer by Theo(3464)

Question 428037: in a certain statistics class, the marks obtained by students on a class test followed a normal distribution with a mean of 68 and a standard deviation of 10. What is the probability that the mean test mark from a sample of 25 students from the class was more than 70?
Click here to see answer by stanbon(57379)

Question 428109: As a sample size approaches infinity, how does the student’s t distribution compare to the normal z distribution? When a researcher draws a sample from a normal distribution, what can one conclude about the sample distribution? Explain
Click here to see answer by stanbon(57379)

Question 428120: Thirty percent of people enrolled in stats class miss class following an exam. In a random sample what is the probability that exactly one will miss?
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Question 428096: If a license plate has three letters followed by 3 digits (all letters and numbers can be repeated), what is the probability of getting a plate that has the letters USA followed by a three-digit number divisible by 2
Click here to see answer by stanbon(57379)

Question 428047: Evaluate the following expressions for the given set of scores:
a. ΣX b. ΣX2 c. (ΣX)2 d. Σ2X e. Σ(X – 2)
Scores:
X
0
5
3
2

Click here to see answer by stanbon(57379)

Question 428041: In low-speed crash tests of five SMART cars, the repair costs were computed for a factory-authorized repair center and an independent repair facility. The results are listed in the accompanying table.
a. Is there sufficient evidence to support the claim that the independent center has lower repair costs? Use a 0.05 significance level.
Authorized repair center $797 $571 $904 $1,147 $418
Independent repair center $523 $488 $875 $911 $297

Click here to see answer by stanbon(57379)

Question 428017: Ziggy and Samantha are planning to have four children. If the probability of a girl is 0.51, what is the probability they will have at least 2 girls or exactly one boy
Click here to see answer by stanbon(57379)

Question 428135: : Biting an unpopped kernel of popcorn hurts! As an experiment, a self-confessed connoisseur of cheap popcorn carefully counted 739 kernels and put them in a popper. After popping, the unpopped kernels were counted. There were 82.
(a) Construct a 95 % confidence interval for the proportion of all kernels that would not pop.
(b) Check the normality assumption.
(c) Try the Very Quick Rule. Does it work well here? Why or why not?
(d) Why might this sample not be typical?

Click here to see answer by stanbon(57379)

Question 427994: Suppose one letter is chosen from the alphabet at random.
a. n(S) =
b. The probability that the letter chosen is in the word "mississippi" =
Click here to see answer by stanbon(57379)

Question 427985: a recent report stated that 4% of adults cut their sandwhich in half before eating it. if 10 u.s. adults are selected randomly, what is the probability that
a) at least 6 people cut their sandwhich in half before eating
b) at most 3 people cut their sandwhich in half before eating it
c) (use binomial formula) exactly 4 people cut their sandwhich in half before eating it

Thanks!
Click here to see answer by stanbon(57379)

Question 428144: if p(A)=0.85 find the compliment of A,P OF A COMPLIMENT

Click here to see answer by solver91311(16897)

Question 428301: There are red marbles, blue marbles, and white marbles in a bag. Write the ratio of the number of blue marbles to the total number of marbles.
Click here to see answer by stanbon(57379)

Question 428284: Can someone please help me with this problem I am stuck and confused on normal distribution.
A normal distribution has a mean of 52 and a standard deviation of 4.2 What is the probability of a value between 44.0 and 55.0?
Your help is greatly apprieciated!
Click here to see answer by stanbon(57379)

Question 428251: Evaluate the following expressions for the given set of scores:
a. ΣX b. ΣX2 c. (ΣX)2 d. Σ2X e. Σ(X – 2)
Scores:
X
0
5
3
2

Click here to see answer by stanbon(57379)

Question 428233: Suppose you are asked to pick 3 numbers from 1 to 20 to win a prize. What is the probability that one of the numbers you will pick is the winning number?
Click here to see answer by stanbon(57379)

Question 428232: a couple plans to have 5 children. what is the probability of having exactly two boys?
Click here to see answer by stanbon(57379)

Question 428232: a couple plans to have 5 children. what is the probability of having exactly two boys?
Click here to see answer by Alan3354(30993)

Question 428364: suppose that a judge's decision follows a binomial distribution and that his verdict is correct 90% of the time. in his next 10 decisions, what is the probability that he makes exactly 8 correct decisions?
Click here to see answer by sudhanshu_kmr(1152)

Question 428376: if Z is a normal random variable, then what is P(1.25 less than or equal to z less than or equal to 1.75)?
Click here to see answer by stanbon(57379)

Question 428380: The distribution of the diameters of a particular variety of oranges is approximately Normal with a standard deviation of 0.3 inch. How does the diameter of an orange at the 67th percentile compare with the mean diameter?
Click here to see answer by stanbon(57379)

Question 428384: The KY Department of Natural Resources personnel periodically inspects plots in eastern ky for evidence of elk habitation. suppose that 25% of the plots have evidence of elk habitation. if a sample of 10 were inspected, how would I find the probability that none have evidence of elk habitation?
Click here to see answer by stanbon(57379)

Question 428500: You roll a pair of dice five times. Find the following probability of you getting at LEAST one sum of 7.
I have trouble with the 'at least' and 'at most' probability problems.
is it, 5C1(6/36)^1 (1-30/36)^4 ?
I'm also unsure when to subtract the probability from one or when to not.
I also have to find the probability of getting at most one sum of 7.
Click here to see answer by sudhanshu_kmr(1152)

Question 428477: A card is drawn from a standard deck of cards. What is the probability the card will be a king or less than a six?
Click here to see answer by rfer(12666)

Question 428557: It has been observed that electrical connectors manufactured by Jolt Electrical Supply Company last an average of 18.2 months and follow a normal distribution with a standard deviation of 1.7 months. Jolt agrees to replace any connector that fails within 19 months. Out of 500 connectors sold, how many does Jolt expect to replace, on average?
Click here to see answer by stanbon(57379)

Question 428532: i need to find the z values for a normal distribution
were the mean is 75 and standard deivation is 21
- the probability that exceeds 19%
Click here to see answer by stanbon(57379)

Question 428590: Because of the relatively high interest rates, most consumers attempt to pay off their credit card bills promptly. However, this is not always possible. An analysis of the amount of interest paid monthly by a bank's Visa cardholders reveals that the amount is normally distributed with a mean of 29 dollars and a standard deviation of 6 dollars.
What interest payment is exceeded by only 21% of the bank's Visa cardholders??
Click here to see answer by stanbon(57379)

Question 428662: A bag contains 12 blocks. Six are red, two are blue, and three are green, and the rest are yellow. If one block is chosen at random and not replaced and then a second block is chosen randomly, what is the probability that both blocks are red?
Click here to see answer by htmentor(789)

Question 428689: Two cards are drawn from an ordinary deck of 52 cards. The probability that both cards are aces is?
Click here to see answer by John10(245)

Question 428698: A bag contains 3 red beads and 5 yellow beads. One bead is removed at random then replaced. This is done three times in total.
Find the probability that:
a) Each bead is red
b)Exactly two beads are red and one bead is yellow
c)At least one bead is red
Click here to see answer by stanbon(57379)

Question 428840: The probability that I will win the two-digit Daily Number Game on any given day is 1/100. Suppose that I play that Game every day for fifty days. Find the chance that I will win at least once.
Thank you!
Click here to see answer by stanbon(57379)

Question 428822: Hi, I am having a very hard time solving this stats problem and if someone could give me some assistance I would be ever greatful. The question is as follows. "There is a new game and a friend asks your advice on playing it. Like yahtzee, it is played with 5 fair sided dice. The game costs $1 to play. The player wins $50 for rolling a total greater than 27. What is your friends expected gain or loss for one play? Be sure to consider all possible cases" I am pretty sure that I should use a multinomial for this problem but I don't have any idea how to set it up. I would appreciate it very much if someone could run me through how to do it.
Click here to see answer by stanbon(57379)

Question 428865: publishing scientific papers online is fast, and the papers can be long. Publishing in a paper journal means that the paper will live foreve in libraries. the british Medical Journal combines the two:it prints short and reasable versions, with longer verison available online/ ots this OK with authors? the journal asked about a random sample of 104 of its recent authors several questions. one question was " should the journal using this system?" in the sample 72 said " yes." (a) do the data give good evidence that more than two-thirds (67%) of authors support continuing this system? carry out an appropriate test to help answer this question. (b) interpret the p-values from your test in the context of the problem.

Click here to see answer by stanbon(57379)

Question 428852: three dice are rolled all at once. What is the probability, to the nearest hundredth, that each dice will show a number greater than 4?
Record your answer and fill in the bubbles on your answer document. Be sure to use the correct place value.
Click here to see answer by sudhanshu_kmr(1152)

Question 428873: An assassin has a kill probability of 0.15(or 15%). Eleven assassins independently shoot, all at the same time, at a noted world leader. Find the chance that he is killed.
Thanks
Click here to see answer by robertb(4012)

Question 428882: Suppose a test given to students has a mean of 500 and standard deviation of 50 and the test scores are normally distributed.
What is the probablity that a single random student has a score between 495 and 503?
What is the shape, mean and standard deviation of the sampling distribution of mean(x bar) is based of a sample of n=36 randomly selected students?
Click here to see answer by stanbon(57379)

Question 428936: Using the formula for the multinomial distribution, the probability of X1=1, X2=1, X3=3, when N=5, P1=0.4, P2=0.4, and P3=0.2 is what? Please write out solution so I can see who the answer was obtained.
Click here to see answer by robertb(4012)

Question 428947: How many ways can 5 supranos and 4 altos be selected from 7 sopranos and 9 altos
Click here to see answer by robertb(4012)

Question 428949: Using the formula for the multinomial distribution, the probability of X1=2, X2=1, X3=1 when N=4, P1=0.3, P2=0.5, P3=0.2 is what? Please write out your answer. Thanks!!
Click here to see answer by robertb(4012)

Question 428954: What is the z value such that 50% of the total area lies to the right of the curve in any normal distribution?
Click here to see answer by robertb(4012)

Question 428960: If X is a normal random variable with a mean of 6 and a standard deviation of 3.0, then find the value x such that P(Z>x)is equal to .7054.
Click here to see answer by stanbon(57379)

Question 428785: Hi, I need help with this math question please. If I wanted to have an equal chance of taking out a red block or blue block, I would put in how many red blocks?
There are currently three blocks in a bag.
Click here to see answer by stanbon(57379)

Question 429058: Before being allowed to enter a maximum security area at a military installation, a person must pass 3 identification tests: a voice pattern test, a fingerprint test, and a handwriting test. If the reliability of the first test is 97%m the reliability of the second test is 98.5%, and the third is 98.5%m what is the probability that this security system will allow an improperly identified person to enter the maximum security area?
Thx any help is appreciated
Click here to see answer by ewatrrr(10682)

Question 429153: In some cases, there are more than two groups that we want to compare. We will be learning the one-factor ANOVA for this analysis. Provide a business example where you would need to compare more than two groups for a significant difference in the means. Provide the hypothesis and the decision rule for your example.
Click here to see answer by stanbon(57379)

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