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July 23, 2014

Homework Help: Math: Statistics

Recent Homework Questions About Statistics

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Statistics
Determine the minimum sample size required in order to be 95% confident that our estimate is within 4% of the true percent of all US households using e-mail. Assume no prior estimate available.
Monday, March 17, 2014 at 7:01pm

statistics
a resturant must choose 5 employees from 12 applicants. in how many ways can they do that?
Monday, March 17, 2014 at 5:43pm

statistics
a machine has 0.04 probability of producing a defective item. If it produces 6 items find: a. probability none is defective b. at least one is defective c. all are defective
Monday, March 17, 2014 at 5:41pm

statistics
a quiz had 6 questions, each with 4 possible answers (only one of which is correct). If you answer them at random, find the probability that all are correct and at least one is wrong.
Monday, March 17, 2014 at 3:12pm

statistics
A clinical trial test a method designed to increase probability of conceiving a girl.In study 375 were born and 300 were girls Use sample data to construct 99%confidence interval of percentage girls born
Monday, March 17, 2014 at 12:28pm

Statistics
A standard pack of 52 cards consists of 4 suits, hearts, diamonds, clubs and spades. Each suit has 13 cards, from Ace to King. We deal randomly 5 cards from the deck of 52. 2 deals differing only by the order are considered the same. How many different deals are there? How ...
Monday, March 17, 2014 at 3:35am

Statistics
Compare the standard deviation for the heights of males and the standard deviation for the heights of females in the class.
Sunday, March 16, 2014 at 1:18am

statistics
A food manufacturer samples 7 bags of pretzels off the assembly line and weighs their contents. If the sample mean is 14.2 oz and the sample standard deviation is 0.60 oz., find the 95% confidence interval of the true mean.
Sunday, March 16, 2014 at 1:00am

statistics
Canadians are becoming more conscious of the importance of good nutrition, and some researchers believe that we may be altering our diets to include less red meat and more fruits and vegetables. To test this theory, a researcher decides to select hospital nutritional records ...
Saturday, March 15, 2014 at 3:14am

statistics
Which two scales of measurement always require nonparametric procedures and why?
Friday, March 14, 2014 at 2:50am

probability and statistics
a multiple choice test onsists of 8 questions, each with 4 possible answers but only one of which is correct.what is the probability that an unprepared student will, by chance, get, a. all correct answers, b. exactly 5 correct answers, c. at most 4 correct answers, d. at most ...
Wednesday, March 12, 2014 at 5:04am

Statistics
An industrial engineer has found that the standard household light bulbs produced by a certain manufacturer have a useful life that is normally distributed with a mean of 250 hours and a variance of 2500. (a) What is the probability that a randomly selected bulb from this ...
Tuesday, March 11, 2014 at 10:09am

6th grade math - statistics
Can you explain why Q1 = 3.5 and Q3 is 9 out of this dataset 0, 1, 3, 4, 6, 7, 7, 7, 8, 10, 12, 12. My answers were: Assuming median would be 7 (using numbers in positions 6 and 7 where 7+7/2 = 7) Q1 dataset would be 0,1,3,4,6; Q1 = 3 Q2 dataset would be 7,8,10,12,12; Q3= 10 ...
Monday, March 10, 2014 at 5:17pm

Statistics
In an experiment, you measure the popularity of two brands of soft drinks (factor A), and for each brand you test males and females (factor B). The following table shows the main effect and cell means from the study: Factor A Level A1: Level A2: Brand X Brand Y Level B1: 14 23...
Monday, March 10, 2014 at 1:03pm

Statistics
A researcher investigated the effect of volume of background noise on participants’accuracy rates while performing a difficult task. He tested three groups of randomly selected students and obtained the following means and sums of squares: Volume Source Sum of sqs. df ...
Monday, March 10, 2014 at 11:13am

statistics
1. A company decides to add a new program that prepares randomly selected sales personnel to increase their number of sales per month. The mean number of sales per month for the overall population of sales people at this national company is 25 with a standard deviation of 4. ...
Monday, March 10, 2014 at 1:04am

Statistics
What is 0.095 on the z-score table or where
Sunday, March 9, 2014 at 8:59pm

statistics
Assuming that the distribution is normal for weight relative to the ideal and 99% of the male participants scored between (–53.68, 64.64), where did 95% of the values for weight relative to the ideal lie? R
Sunday, March 9, 2014 at 4:22pm

Statistics
Put in Binomial Probability Formula? probability ( 2 of 22 are lost) = C(22,2) (1/200)^2 (199/200)^20
Sunday, March 9, 2014 at 6:59am

Statistics
List five numbers for which the sample mean is 30 and not all numbers are equal and would have a mean of 30 but all numbers are equal
Sunday, March 9, 2014 at 3:24am

Statistics
How do I plug this into the Binomial Probability Formula? prob(lost) = 5/1000 = 1/200 prob(not lost) = 199/200 prob( 2 of 22 are lost) = C(22,2) (1/200)^2 (199/200)^20 = .005224..
Sunday, March 9, 2014 at 12:45am

Statistics
Prev Up Next (1 pt) Suppose that in the year 2000, the cost of a compact car averaged $ 12600 and that in 2003, the cost averaged $ 14100. Assuming that the relationship between year t and cost c is linear, develop a formula for predicting the average cost of a compact car in ...
Saturday, March 8, 2014 at 5:14pm

Statistics
I have 8 marbles: 3 blue, 1 green, 4v reds. What is the probability of selecting a blue marble twice with replacement and twice without replacement
Saturday, March 8, 2014 at 12:09pm

Statistics
For the z-score mean-SD how do you get the percentage without using a calculator
Saturday, March 8, 2014 at 11:22am

Statistics
If I don't know the mean and the standard deviation how can I find the area of z-score -0.75
Saturday, March 8, 2014 at 10:28am

Statistics
If I don't know the mean and the standard deviation how can I find the area of z-score -0.75
Saturday, March 8, 2014 at 9:06am

Statistics
Consider the standard normal distribution. Find the area for the z-score -0.75. Draw a picture of this distribution showing the location of the z-score and the mean. Shade the region corresponding to the area found for the z-score.
Saturday, March 8, 2014 at 8:37am

Statistics
In a certain population of clover, the number of flowers on each plant is approximately normally distributed with a mean of 10.8 flowers/plant and a standard deviation of 2.1 flowers/plant. What percentage of the plants fall between 8 and 11 flowers?
Saturday, March 8, 2014 at 7:09am

statistics
In a random sample of 100 customers, 62 returned with a month. For a 95% confidence interval on the proportion of customers who return for an oil change, the lower limit is:
Friday, March 7, 2014 at 11:21pm

Statistics
Help please... What are some reason for conducting an experiment with two factors?
Friday, March 7, 2014 at 3:16pm

statistics
a large shipment of computer chips, of which 5% are actually defective, a quality control manager decides to test chips until he finds the first defective. What is the probability that the manager finds the first defective chip on the first test? in Homework Help
Friday, March 7, 2014 at 4:04am

Statistics
If the king and queen invite 8 knights and thier wives then how many handshakes will there be if each couple cannot handshake with their lifetime partner. (I think this involves the king and queen as a couple).
Thursday, March 6, 2014 at 9:55am

statistics
Post a null hypothesis that would use a t test statistical analysis.. Use the same hypothetical situation taken in the t test hypothesis, and turn it into a null hypothesis using a one-way ANOVA analysis and a two-way ANOVA.
Wednesday, March 5, 2014 at 11:49am

statistics
A telephone company's records indicate that private customers pay on average $17.10 per month for long-distance telephone calls. A random sample of 10 customers' bills during a given month produced a sample mean of $22.10 expended for long-distance calls and a sample ...
Wednesday, March 5, 2014 at 11:45am

statistics
Post a null hypothesis that would use a t test statistical analysis.. Use the same hypothetical situation taken in the t test hypothesis, and turn it into a null hypothesis using a one-way ANOVA analysis and a two-way ANOVA.
Wednesday, March 5, 2014 at 11:22am

statistics
Conduct an ANOVA comparing participants recall will vary as a function of stress levels. Conduct an ANOVA comparing participants recall at Time 1 across all three stress level conditions (low, medium,and high). Conduct post hoc tests if needed, using the Tukey method.
Monday, March 3, 2014 at 8:12pm

statistics
Conduct an ANOVA comparing participants recall will vary as a function of stress levels. Conduct an ANOVA comparing participants recall at Time 1 across all three stress level conditions (low, medium, and high). Coduct post hoc tests if needed, using the Tukey method.Write a ...
Monday, March 3, 2014 at 3:31pm

statistics
On the average five customers visit a children department store each hour. Using Poisson distribution, calculate the probability of three customers shop at the store.
Monday, March 3, 2014 at 12:17pm

statistics
the average score on the statistics quiz was a 70, and there was a standard deviation of 10 points. If the z-socre was -1.0 what is the percentile rank?
Sunday, March 2, 2014 at 1:04pm

Statistics
In a certain city of several million people, of the adults are unemployed. If a random sample of adults in this city is selected, approximate the probability that at least in the sample are unemployed. Use the normal approximation to the binomial with a correction for ...
Saturday, March 1, 2014 at 8:56pm

Statistics
An economist found that a random sample of 42 high school teachers had an average annual salary of $56,490. A previous study showed that the population standard deviation is $4150. Calculate the margin of error, E, for a 99% confidence interval for µ, the average annual ...
Saturday, March 1, 2014 at 5:26pm

statistics
A survey among US adults of their favorite toppings on a cheese pizza reported that 43% favored pepperoni, 14% favored mushrooms, and 6% favored both pepperoni and mushrooms. What is the probability that a random adult favored pepperoni or mushrooms on their cheese pizza? ...
Friday, February 28, 2014 at 8:56pm

Probability
Statistics show that about 5% of all males are colorblind. Suppose that 20 males are selected at random. What is the probability that at least 4 of the 20 people are colorblind? My answer: I got 1-0.984 The answer key says 0.00257394
Friday, February 28, 2014 at 7:49pm

statistics
When calculating a confidence interval for the difference between two means, what information are you gaining? The means are from both same population and different? Thank you.
Friday, February 28, 2014 at 4:47pm

Math (Statistics)
The SAT scores of a certain population of students are approximately normally distributed with a mean and standard deviation of 1000 and 200 points, respectively. The probability that a student selected at random from the population has an SAT score between 800 and 1200 ...
Friday, February 28, 2014 at 3:20pm

Statistics
Assume it is known that the probability of birth is equal in all months. What is the probability that in the STAT class of 120 students, exactly 20 students have their birthdays in either August or September? Solve using (i) the exact Binomial distribution, (ii) the Normal ...
Friday, February 28, 2014 at 9:56am

Statistics
Two of the biggest soft drink rivals, Pepsi and Coke, are very concerned about their market shares. The pie chart that follows claims that PepsiCo's share of the beverage market is 25%. Assume that this proportion will be close to the probability that a person selected at ...
Friday, February 28, 2014 at 9:02am

Statistics
When calculating a confidence interval for the difference between two means, what information are one gaining?
Friday, February 28, 2014 at 8:49am

Statistics
Let X be a binomial random variable with n = 100 and p = 0.2. Find approximations to these probabilities. (Round your answers to four decimal places.) P(17 < X < 28) I get the answer as 0.7059 but it is wrong. I can't seem to figure this out... Help please
Thursday, February 27, 2014 at 11:57pm

engineering
Building and construction A. Architecture B. Engineering C. Nursing D. Statistics
Thursday, February 27, 2014 at 8:53pm

statistics
You have a score on a national entrance exam of 95. What percentage of people in the population have a score that is lower than yours? (Assume the population mean is 75 and the standard deviation is 10. Use the table I passed out in class.)
Wednesday, February 26, 2014 at 11:47am

Statistics
A report says that the between-subjects factor of participants’ salary produced significant differences in self-esteem. (a) What does this tell you about the design? (b) What does it tell you about the results?
Wednesday, February 26, 2014 at 10:43am

Statistics
A report says that the between-subjects factor of participants’ salary produced significant differences in self-esteem. (a) What does this tell you about the design? (b) What does it tell you about the results? 19.(a) Source Sum Squares df Mean Square F Between 134.800 3 ...
Wednesday, February 26, 2014 at 10:41am

Statistics in Psychology
Please Help! For the following, which type of t-test is required? (a) Studying the effects of a memory drug on Alzheimer’s patients, testing a group of patients before and after administration of the drug. (b) Studying whether men and women rate the persuasiveness of an ...
Wednesday, February 26, 2014 at 9:11am

behavioral statistics
How could you use standard scores and the standard distribution to compare the reading scores of two students receiving special reading resource help and one student in a standard classroom who does not get special help?
Tuesday, February 25, 2014 at 8:29pm

Statistics
The weights of male babies less than 2 months old in the United States is normally distributed with a mean of 11.5 pounds and a standard deviation of 2.7 pounds. Find the 80th percentile score for these weights. I don't have a table, I have to figure it out using the TI-84...
Tuesday, February 25, 2014 at 7:13pm

Statistics
The law of large numbers tells us what happens in the long run. Like many games of chance, the numbers racket has outcomes so variable - one three-digit number wins $600 and all others win nothing - that gamblers never reach "the long run." Even after many bets, ...
Tuesday, February 25, 2014 at 7:10pm

Statistics 101
A researcher plans to use a random sample of n= 500 families to estimate teh mean monthly family incomefor a large population. a 99% confidence interval based on the sample would be _________ than 90% confidence interval.
Tuesday, February 25, 2014 at 6:43pm

Statistics
The weights of male babies less than 2 months old in the United States is normally distributed with a mean of 11.5 pounds and a standard deviation of 2.7 pounds. Find the 80th percentile score for these weights.
Tuesday, February 25, 2014 at 6:18pm

Statistics
The law of large numbers tells us what happens in the long run. Like many games of chance, the numbers racket has outcomes so variable - one three-digit number wins $600 and all others win nothing - that gamblers never reach "the long run." Even after many bets, ...
Tuesday, February 25, 2014 at 5:39pm

statistics
Suppose a manufacturer claims that each family-size bag of pretzels sold weighs 12 ounces on average with a standard deviation of 0.8 ounces. A consumer's group decides to test this claim. If a simple random sample of 49 bags of pretzels gives a sample mean of 11.8 ounces...
Tuesday, February 25, 2014 at 5:31pm

Statistics
The law of large numbers tells us what happens in the long run. Like many games of chance, the numbers racket has outcomes so variable - one three-digit number wins $600 and all others win nothing - that gamblers never reach "the long run." Even after many bets, ...
Tuesday, February 25, 2014 at 3:13pm

Statistics
A class survey in a large class for first-year college students asked, "About how many minutes do you study on a typical weeknight?" The mean response of the 463 students was x = 118 minutes. Suppose that we know that the study time follows a Normal distribution with...
Tuesday, February 25, 2014 at 11:11am

Statistics
In a study, nine tires of a particular brand were driven on a track under identical conditions. Each tire was driven a particular controlled distance (measured in thousands of miles), and afterward the tread depth was measured. Tread depth is measured in “mils.” Here...
Tuesday, February 25, 2014 at 7:23am

statistics
Determining whether an individual's political affliation affects his or her overall satisfaction with the economy. For this assignment, use only subjects that declared themselves as Republicans or Democrats and leave out any subjects who declared themselves as Independent ...
Tuesday, February 25, 2014 at 12:47am

statistics
A psychic was tested for ESP. The psychic was presented with 400 cards face down and was asked to determine if the card was one of four symbols: a cross, a star, a circle, or a square. The psychic was correct in 120 of the cases. Let p represent the probability that the ...
Monday, February 24, 2014 at 7:25pm

statistics
An SRS of 40 San Diego County Schools graduates showed that 26 of the 40 enrolled in a college or university right out of high school. a. Find a 90% confidence interval for the proportion of all San Diego County Schools graduates who enrolled in a college or university right ...
Monday, February 24, 2014 at 6:19pm

Statistics
Fill in the blanks with the appropriate raw score, z score, t scores . Mean =50, sd = 5. Raw 35
Sunday, February 23, 2014 at 10:16pm

statistics
Construct a 95% confidence interval for the population mean. 5. Airfare A random sample of airfare prices (in dollars) for a one-way ticket airfare between two cities MN. Key: 21|1=211 21 | 1 2 22 | 1 1 1 2 3 5 7 8 23 | 2 3 4 7 7 8 9 9 24 | 2 3 4 8 8 25 | 1 2 6 6 6 6 8 9
Sunday, February 23, 2014 at 9:37pm

statistics
Construct a 95% confidence interval for the population mean. 5. Airfare A random sample of airfare prices (in dollars) for a one-way ticket airfare between two cities MN. Key: 21|1=211 21 | 1 2 22 | 1 1 1 2 3 5 7 8 23 | 2 3 4 7 7 8 9 9 24 | 2 3 4 8 8 25 | 1 2 6 6 6 6 8 9
Sunday, February 23, 2014 at 9:29pm

Statistics
Summarize the steps involved in analyzing the results of a one-sample experiment.
Sunday, February 23, 2014 at 2:29am

Statistics
If you pick a card at random from a well shuffled deck what is the probability you will pick a face card or a spade?
Saturday, February 22, 2014 at 4:08pm

statistics
a packaging device is set to fill detergent powder packets with a mean weight of 5kg.The standard deviation is known to be .01kg.these are known to drift upwards over a period of time due to machine fault which is not tolerable. A random sample of 100 packets is taken and ...
Saturday, February 22, 2014 at 9:48am

statistics
Use a table of t-values to estimate the P-value for the specified one-mean t-test. Left-tailed test, n=12, t= -3.412. a=p<0.005. b= p>0.005. c= 0.005<p<0.01.
Friday, February 21, 2014 at 8:09pm

Statistics
Selecting a letter of the alphabet: If 3 letters of the alphabet are selected at random, find the probability of getting at least one letter "x". Letters can be used more than once. My answer was: P(at least 1 "x) = 1 - (25/26)^3 = 1951/17576 or 0.11 Is this ...
Friday, February 21, 2014 at 11:56am

statistics
Simple question I may be over thinking 30. Gift Baskets: The Gift Basket Sore had the following premade gift baskets containing the following combinations in stock. cookies mugs candy -------------------------------------- coffee 20 13 10 tea 12 10 12 Choose 1 basket at random...
Thursday, February 20, 2014 at 11:55pm

statistics
A population is normally distributed with mean 30, population SD =10, Sample size 25. What are the mean and variance of the distribution of means, respectively?
Thursday, February 20, 2014 at 10:35pm

Statistics
Astronomers treat the number of stars in a given volume of space as a Poisson random variable. The density in the Milky Way Galaxy in the vicinity of our solar system is one star per 16 cubic light years. (a) What is the probability of three or more stars in 16 cubic light ...
Thursday, February 20, 2014 at 8:16pm

Statistics
An electronic product contains 32 integrated circuits. The probability that any integrated circuit is defective is 0.02, and the integrated circuits are independent. The product operates only if there are no defective integrated circuits. What is the probability that the ...
Thursday, February 20, 2014 at 7:41pm

Statistics
2. On a certain anxiety questionnaire, the population is known to have a mean of 12 and a standard deviation of 2.3. A higher score represents higher levels of anxiety. Participants in a new relaxation program complete the questionnaire after completing the program, and have a...
Wednesday, February 19, 2014 at 11:22am

Statistics
1. A company decides to add a new program that prepares randomly selected sales personnel to increase their number of sales per month. The mean number of sales per month for the overall population of sales people at this national company is 25 with a standard deviation of 4. ...
Wednesday, February 19, 2014 at 11:20am

statistics
Suppose you have information that the average stress score of students in online activities is 13.15. Using Minitab, compute a one sample t-test to find out whether the stress scores reported by your sample are significantly different from those of the population of online ...
Wednesday, February 19, 2014 at 9:01am

Statistics
Disk of ploycarbonate plastic form a supplier are anaylzed for scratcha nd shock resistance. the results from 100 disks are summarized below: Shock Resistance high low Scratch high 70 9 resistance low 16 5 Let A denote the even that a disk has high shock resistance, and let B ...
Tuesday, February 18, 2014 at 5:38pm

Statistics
The probability that Jack plays guitar on a raining day is 0.6 and on a sunny day is 0.5. The probability that is rains tomorrow is 0.8. Find the probability that Jack will not play guitar tomorrow? Is it 32%?
Tuesday, February 18, 2014 at 5:19pm

Statistics
Hats in a box problem
Tuesday, February 18, 2014 at 4:37pm

statistics
Suppose you have information that the average stress score of students in online universities is 13.15. The scores are 16, 20, 15, 12, and 14
Tuesday, February 18, 2014 at 10:24am

statistics
The personnel office at a large electronics firm regularly schedules job interviews and maintains records of the interviews. From the past records, they have found that the length of a first interview is normally distributed, with mean μ = 31 minutes and standard ...
Tuesday, February 18, 2014 at 1:04am

statistics
The taxi and takeoff time for commercial jets is a random variable x with a mean of 8.4 minutes and a standard deviation of 3 minutes. Assume that the distribution of taxi and takeoff times is approximately normal. You may assume that the jets are lined up on a runway so that ...
Tuesday, February 18, 2014 at 1:01am

statistics
Suppose x has a normal distribution with mean μ = 35 and standard deviation σ = 9. (a) Describe the distribution of x values for sample size n = 4. (Use 2 decimal places.) μx = σx = (b) Describe the distribution of x values for sample size n = 16. (Use 2 ...
Tuesday, February 18, 2014 at 1:00am

statistics
Suppose that each unit of a system is up with probability 2/3 and down with probability 1/3. Different units are independent. For each one of the systems shown below, calculate the probability that the whole system is up (that is, that there exists a path from the left end to ...
Monday, February 17, 2014 at 8:34pm

statistics
Researchers found that 30% of the larch trees in a certain geographical area had been damaged by fungi. (No fun, guy.) Consider a sample of 20 (independent) beach trees from the area. (a) What is the probability that fewer than half are damaged by fungi? (b) What is the ...
Sunday, February 16, 2014 at 3:22pm

Statistics
a) What is sampling with replacement? (b) What is sampling without replacement? c) How does sampling without replacement affect the probability of events, compared to sampling with replacement?
Sunday, February 16, 2014 at 3:30am

statistics
Below are six data sets with 6 randomly selected scores in each data set. Your task is to determine if the scores were drawn from a population with μ = 5. Before you calculate the one-sample t test for each sample, make a guess as to whether or not you think the sample ...
Saturday, February 15, 2014 at 12:17pm

Statistics
In the population of typical college students, _ 5 75 on a statistics final exam _X 5 6.42 . For 25 students who studied statistics using a new technique, X 5 72.1. Using two tails of the sampling distribution and the .05 criterion: (a) What is the critical value? (b) Is this ...
Friday, February 14, 2014 at 6:57am

Statistics
There are 100 questions from a SAT test, and they are all multiple choice with possible answers of a,b,c,d,e for each question only one answer is correct. Find the mean number of correct answers for those who make random guesses for all 100 questions?
Thursday, February 13, 2014 at 1:09pm

Statistics
The mean of a population of raw scores is 33 1_X 5 122 . Use the criterion of .05 and the upper tail of the sampling distribution to test whether a sample with X 5 36.8 1N 5 302 represents this population. (a) What is the critical value? (b) Is the sample in the region of ...
Thursday, February 13, 2014 at 2:09am

Statistics
Foofy asks a sample of students their choice in the election for class president. concludes that Poindexter will win. It turns out that Dorcas wins. What is the statistical explanation for Foofy’s erroneous prediction?
Thursday, February 13, 2014 at 1:57am

Statistics
A couple with eight daughters decides to have one more baby, because they think this time they are sure to have boy! Is this reasoning accurate?
Thursday, February 13, 2014 at 1:55am

Statistics
Height (ft) Interval after (min) 96 68 111 80 76 66 91 72 66 58 108 79 116 84 91 79 The data show the time intervals after an eruption (to the next eruption) of a certain geyser. Find the regression equation, letting the first variable be the independent (x) variable. Find the...
Wednesday, February 12, 2014 at 10:15pm

Statistics
A clinical trial tests a method designed to increase the probability of conceiving a girl. In the study 624 babies were born, and 312 of them were girls. Use the sample data to construct a 99% confidence interval estimate of the percentage of girls born. Based on the result, ...
Wednesday, February 12, 2014 at 10:14pm

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