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Tutors Answer Your Questions about Probability-and-statistics (FREE)
Question 184598: Hi can you please help me solve for this:
The monthly sales volume (in thousands of dollars) for a manufacturer of snow skis is seasonal (there tend to be more skis sold during fall and winter months than during warmer months). The following table shows the monthly seasonal indexes for the company's sales:
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
1.16 0.99 0.91 0.70 0.61 0.49 0.69 1.00 1.26 1.29 1.47 1.47
Using several years of sales data, beginning in September of (i.e., corresponds to September of ), the manufacturer summarized that the trend line that describes the monthly sales (in thousands of dollars) has the form . Assuming that a multiplicative model can be used to describe the sales data, generate a forecast for the total dollar sales the company can expect to receive in February of .
Express your answer in thousands of dollars.
Thank you
Click here to see answer by stanbon(26259)   |
Question 184595: Could someone help me solve this please? Thank you
34 Grace took a random sample of the number of steps per minute from the electronic readout of her aerobic climbing machine during a 1-hour workout. (a) Calculate the mean, median, and mode.(b) Which is the best measure of central tendency? The worst? Why?
134
72
72
58
65
151
98
67
41
101
107
119
22
64
67
Click here to see answer by stanbon(26259) |
Question 184594: could someone help me solve this please. thank you.
: Identify the following variables as likely having either nominal, ordinal or interval/ratio level of measurement.
a) Cups of coffee consumed in a week
b) Eye color of a survey respondent
c) Household income by range (i.e., $0 - $20,000; $20,001 - $40, 000, etc.)
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Question 184592: Could someone help me solve this please! Thank you
A sample of eight tourists leaving Hawaii was taken on how many rolls of film were shot during your stay on the island. What is the standard deviation for this sample?
6
7
9
11
7
10
8
6
Click here to see answer by stanbon(26259) |
Question 184680: Hi I'm not sure what the form not showing up means, but if the problem is visible now that I retyped it can someone please help me solve for it?
The monthly sales volume (in thousands of dollars) for a manufacturer of snow skis is seasonal (there tend to be more skis sold during fall and winter months than during warmer months). The following table shows the monthly seasonal indexes for the company's sales:
Jan. 1.16 Feb .99 Mar .91 Apr .70 May .61 Jun .49 Aug 1.00 Sep 1.26 Oct 1.29 Nov 1.47 Dec 1.47
Using several years of sales data, beginning in September of (i.e., corresponds to September of ), the manufacturer summarized that the trend line that describes the monthly sales (in thousands of dollars) has the form . Assuming that a multiplicative model can be used to describe the sales data, generate a forecast for the total dollar sales the company can expect to receive in February of .
Express your answer in thousands of dollars.
Thank you
Click here to see answer by solver91311(5072)  |
Question 184727: Iam am taking statistics and I am having trouble with my homework.
Normal Distributions: Finding Values
1. Answer the questions about the specified normal distribution.
a.The lifetime of ZZZ batteries are normally distributed with a mean of 270 hours and a standard deviation of 10 hours. Find the number of hours that represent the the 40th percentile.
b.Scores on an English placement test are normally distributed with a mean of 55 and standard deviation of 6.5. Find the score that marks the top 5%.
Sampling Distribution and the Central Limit Theorem
2. Find the probabilities.
a.From National Weather Service records, the annual snowfall in the TopKick Mountains has a mean of 92 inches and a standard deviation of 12 inches. If the snowfall from 36 randomly selected years are chosen, what it the probability that the snowfall would be less than 95 inches?
b. The loan officer rates applicants for credit. Ratings are normally distributed. The mean is 240 and the standard deviation is 60. If 49 applicants are randomly chosen, what is the probability that they will have a rating between 230 and 260? Round z scores to two decimal places.
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Question 184725: I am having trouble in my statistics class with my homework, would someone please help me again. I have two questions.
Normal Distributions: Find Probabilities
1. The diameters of a wooden dowel produced by a new machine are normally distributed with a mean of 0.55 inches and a standard deviation of 0.01 inches. What percent of the dowels will have a diameter less than 0.56?
2. The a loan officer rates applicants for credit. Ratings are normally distributed. The mean is 240 and the standard deviation is 50. Find the probability that an applicant will have a rating less than 300.
Thank you very much in advance for helping me.
Click here to see answer by stanbon(26259) |
Question 184919: An aptitude test has a mean of 220 and a standard deviation of 10, find the corresponding z score for: a) a test score of 232, b)a test score of 212.
Thanks much- I just am having an awful time with stats!
Click here to see answer by stanbon(26259) |
Question 185097: Please Please help me solve this problem! Can anyone help me? It will be greatley appreciated! Thank you so much for your time!!
Grace took a random sample of the number of steps per minute from the electronic readout of her aerobic climbing machine during a 1-hour workout. (a) Calculate the mean, median, and mode.(b) Which is the best measure of central tendency? The worst? Why?
97
84
87
64
65
104
15
102
108
98
Click here to see answer by stanbon(26259) |
Question 185237This question is from textbook 
: Seven girls and six boys walk into a video store at the same time. There are five salespeople available to help them. Find the probability that the salespeople will first help the given numbers of girl and boys.
P(all girls or all boys)This question is from textbook
Click here to see answer by Edwin McCravy(2920) |
Question 185248: Bag contains marbles of 5 diff colors, 9 of each color. You select 4. How many diff ways can you choose 2 of one color, 1 of another color and 1 of yet another color?
I would have thought it was 9C2 x 9C1 x9C1 x 5C3 (5 colors, choose 3), but I know this isn't the answer. Can anyone assist?
Click here to see answer by stanbon(26259) |
Question 185310: There are 7 girls in a bus. Each girl has 7 backpacks.
In each backpack, there are 7 big cats. For every big cat, there are 7 little cats.
The bus driver is not in the bus at this time.
Question:
How many legs are there in the bus?2,401
Click here to see answer by Daffy Duck(1) |
Question 185312: There are 7 girls in a bus. Each girl has 7 backpacks.
In each backpack, there are 7 big cats. For every big cat, there are 7 little cats.
The bus driver is not in the bus at this time.
Question:
How many legs are there in the bus?
Click here to see answer by vleith(1977) |
Question 185365This question is from textbook Applied Statistics in Business & Economics
: A random sample of 10 miniature Tootsie Rolls was taken from a bag. Each piece was weighed on a very accurate scale. The results in grams were 3.087 3.131 3.241 3.241 3.270 3.353 3.400 3.411 3.437 3.477 (a) Construct a 90 percent confidence interval for the true mean weight. (b) What sample size would be necessary to estimate the true weight with an error of ± 0.03 grams with 90 percent confidence? (c) Discuss the factors which might cause variation in the weight of Tootsie Rolls during manufacture. (Data are from a project by MBA student Henry Scussel.This question is from textbook Applied Statistics in Business & Economics
Click here to see answer by stanbon(26259) |
Question 185150This question is from textbook Applied Statistics
: The probability is 1 in 4,000,000 that a single auto trip in the United States will result in a fatality. Over a lifetime, an average U.S. driver takes 50,000 trips. (a) What is the probability of a fatal accident over a lifetime? Explain your reasoning carefully. Hint: Assume independent events. Why might the assumption of independence be violated? (b) Why might a driver be tempted not to use a seat belt “just on this trip”?
This question is from textbook Applied Statistics
Click here to see answer by stanbon(26259) |
Question 185306: An auditor reviewed 25 oral surgery insurance claims from a particular surgical office, determining that the mean out-of-pocket patient billing above the reimbursed 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(26259) |
Question 185152This question is from textbook Applied Statistics
: In 1992, the FAA conducted 86,991 pre-employment drug tests on job applicants who were to be engaged in safety and security-related jobs, and found that 1,143 were positive. (a) Construct a 95 percent confidence interval for the population proportion of positive drug tests. (b) Why is the normality assumption not a problem, despite the very small value of p? (Data are from Flying 120, no. 11 [November 1993], p. 31.)
This question is from textbook Applied Statistics
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Question 171193This question is from textbook
: A club consists of 10 members. In how many different ways can a group of 3 people be selected to go on a European trip?
I came up with the answer of 9
Is that correct?This question is from textbook
Click here to see answer by Alan3354(6059)  |
Question 185452: Can someone please help me solve this and explain why? Thank you
The lifetime of a certain brand of battery is known to have a standard deviation of 10.5 hours. Suppose that a random sample of 120 such batteries has a mean lifetime of 40.9 hours. Based on this sample, find a 95% confidence interval for the true mean lifetime of all batteries of this brand.
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Question 185521: can someone please help me solve this? thanks
At a certain pizza parlor,36 % of the customers order a pizza containing onions,35 % of the customers order a pizza containing sausage, and 66% order a pizza containing onions or sausage (or both). Find the probability that a customer chosen at random will order a pizza containing both onions and sausage.
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Question 185520: can someone please help me solve this? thanks
An ordinary (fair) die is a cube with the numbers 1 through 6 on the sides (represented by painted spots). Imagine that such a die is rolled twice in succession and that the face values of the two rolls are added together. This sum is recorded as the outcome of a single trial of a random experiment.
Compute the probability of each of the following events:
Event a : The sum is greater than .
Event b : The sum is not divisible by and not divisible by .
Write answers as exact fractions
p(a)= ?
p (b)=?
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Question 185519: can someone please help me solve this? thanks
A pizza parlor has a choice of 13 toppings for its pizzas. From these 13 toppings, how many different 4-topping pizzas can be ordered? Assume that the order in which the toppings are listed does not matter.
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Question 185517: can someone please help me solve this? thanks
Polychlorinated biphenyl (PCB) is among a group of organic pollutants found in a variety of products, such as coolants, insulating materials, and lubricants in electrical equipment. Disposal of items containing less than 50 parts per million (ppm) PCB is generally not regulated. A certain kind of small capacitor contains PCB with a mean of 48.3 ppm and a standard deviation of 6 ppm. The Environmental Protection Agency takes a random sample of of these small capacitors, planning to regulate the disposal of such capacitors if the sample mean amount of PCB is 49.5 ppm or more. Find the probability that the disposal of such capacitors will be regulated.
Carry your intermediate computations to at least four decimal places. Round your answer to at least three decimal places.
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Question 185518: can someone please help me solve this. thanks
From a group of 18 customers,5 are to be chosen to receive a special gift. Assuming that the order in which the customers are chosen is irrelevant, how many groups of 5 customers can be chosen?
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Question 185518: can someone please help me solve this. thanks
From a group of 18 customers,5 are to be chosen to receive a special gift. Assuming that the order in which the customers are chosen is irrelevant, how many groups of 5 customers can be chosen?
Click here to see answer by Alan3354(6059) |
Question 185516: can someone please help me solve this? thanks
An aptitude test is designed to measure leadership abilities of the test subjects. Suppose that the scores on the test are normally distributed with a mean of 570 and a standard deviation of 120. The individuals who exceed 800 on this test are considered to be potential leaders. What proportion of the population are considered to be potential leaders? Round your answer to at least four decimal places.
Click here to see answer by stanbon(26259) |
Question 185515: can someone please help me solve this? thank you
Suppose that the heights of adult women in the United States are normally distributed with a mean of 64 inches and a standard deviation of 2.2 inches. Jennifer is taller than 70% of the population of U.S. women. How tall (in inches) is Jennifer? Carry your intermediate computations to at least four decimal places. Round your answer to at least one decimal place.
Click here to see answer by stanbon(26259) |
Question 185510: can someone please help me solve this? thank you
The unemployment rate in a city is %. Find the probability that more than out of people from this city sampled at random are unemployed. Round your answer to four decimal places.
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Question 185509: can someone please help me solve this? thank you
A TV executive is interested in the popularity of a particular cable TV show. She has been told that a whopping of American households would be interested in tuning in to a new network version of the show. If this is correct, what is the probability that all of the households in her city being monitored by the TV industry would tune in to the new show? Assume that the households constitute a random sample of American households.
Round your response to at least three decimal places.
Click here to see answer by stanbon(26259) |
Question 185508: can someone please help me solve this? thank you
Suppose that we've decided to test Clara, who works at the Psychic Center, to see if she really has psychic abilities. While talking to her on the phone, we'll thoroughly shuffle a standard deck of cards (which is made up of hearts, spades, diamonds, and clubs) and draw one card at random. We'll ask Clara to name the suit (heart, spade, diamond, or club) of the card we drew. After getting her guess, we'll return the card to the deck, thoroughly shuffle the deck, draw another card, and get her guess for the suit of this second card. We'll repeat this process until we've drawn a total of cards and gotten her suit guesses for each.
Assume that Clara is not clairvoyant, that is, assume that she randomly guesses on each card.
Estimate the number of cards in the sample for which Clara correctly guesses the suit by giving the mean of the relevant distribution (that is, the expectation of the relevant random variable). Do not round your response.
Quantify the uncertainty of your estimate by giving the standard deviation of the distribution. Round your response to at least three decimal places.
Click here to see answer by stanbon(26259) |
Question 185505: can someone please help me with this? Thank you
Suppose that a researcher is interested in estimating the mean systolic blood pressure, , of executives of major corporations. He plans to use the blood pressures of a random sample of executives of major corporations to estimate . Assuming that the standard deviation of the population of systolic blood pressures of executives of major corporations is mm Hg, what is the minimum sample size needed for the researcher to be confident that his estimate is within mm Hg of ?
Carry your intermediate computations to at least three decimal places. Write your answer as a whole number (and make sure that it is the minimum whole number that satisfies the requirements).
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Question 185504: can someone please help me answer this? thank you
The standard deviation of test scores on a certain achievement test is . A random sample of scores on this test had a mean of . Based on this sample, find a confidence interval for the true mean of all scores. Then complete the table below.
Carry your intermediate computations to at least three decimal places. Round your answers to one decimal place.
what is the lower and upper limit of the 90% confidence interval?
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Question 185674: Can someone please help me solve this? thank you so much
Managers at an automobile manufacturing plant would like to estimate the mean completion time of an assembly line operation, u. The managers plan to choose a random sample of completion times and estimate u via the sample. Assuming that the standard deviation of the population of completion times is 12.3 minutes, what is the minimum sample size needed for the managers to be 95% confident that their estimate is within 1.5 minutes of u?
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Question 185672: Can someone please help me solve this? Thank you so much.
The owner of Britton’s Egg Farm wants to estimate the mean number of eggs laid per chicken. A sample of 25 chickens shows they laid an average of 19 eggs per month with a standard deviation of 2.25 eggs per month.
a. What is the best estimate of the population mean?
b. For a 99 percent confidence interval, what is the value of t?
c. Develop the 99 percent confidence interval for the population mean.
Please identify the lower and upper confidence boundaries.
Click here to see answer by stanbon(26259) |
Question 185747: can someone please help me solve this? thank you so much.
An insurance company is trying to determine, using the 95% confidence level, what proportion of teenagers have an accident. Using a sample of 582 accidents, the company discovers that teenagers were involved in 91 accidents. What is confidence interval for this proportion?
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Question 185745: can someone please help me solve this? thank you so much.
An insurance company is trying to determine, using the 95% confidence level, what proportion of teenagers have an accident. Using a sample of 582 accidents, the company discovers that teenagers were involved in 91 accidents. What is confidence interval for this proportion?
Click here to see answer by stanbon(26259) |
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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
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