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November 25, 2014

Homework Help: Math: Statistics

Recent Homework Questions About Statistics

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statistics
A doctor wants to know if her patients are happy with her. She decides to survey a sample of her clients. What method would be best for choosing a random sample that is a fair representation of her patients? A. Assign numbers to each patient and then use a random number ...
Sunday, July 13, 2014 at 7:16pm

statistics
a rocket club makes its own rockets. The rockets go to a mean height of 1100 feet with a standard deviation of 60 feet. if the club fires 36 rockets, what is probability that the mean heights of the rockets will be greater than 1080p feet
Sunday, July 13, 2014 at 4:15pm

statistics
the heights of the "basketball fans" at a highly anticipated basketball game.
Saturday, July 12, 2014 at 6:27pm

psy 315
using the 5 steps of hypothesis testing begining salary mean =17,016,09,sd7.870 and current salary mean= 34,419.5,7 sd=17,075 with n=474 of employees test statistics = 33.036,p<.05
Friday, July 11, 2014 at 11:37pm

math 200 statistics
ADHD a researcher studying ADHD among teenagers obtains a simple random sample of 100 teenagers aged 13 to 17 and asks them whether or not they have ever been prescribed medication for ADHD. To say that the distribution of sample proportion (P cap), the sample proportion of ...
Friday, July 11, 2014 at 10:44pm

Statistics
A COMMITTEE OF 5 PEOPLE IS TO BE FORMED FROM 15 PARENTS AND 10 teachers. Find the probability that the committee will consist of at least one parent.
Friday, July 11, 2014 at 12:07am

Statistics/probability
The random variable X has a binomial distribution with the probability of a success being 0.2 and the number of independent trials is 15. The random variable xbar is the mean of a random sample of 100 values of X. Find P(xbar<3.15).
Thursday, July 10, 2014 at 3:00pm

Statistics/Probability
The life span of a calculator has a normal distribution with a mean of 60 months and a standard deviation of 5 months. If a calculator is randomly selected, find the probability that the calculator has a life span of. (1) more than 50 months (2) between 4 years and 6 years.
Thursday, July 10, 2014 at 1:56pm

statistics
In the old days, we could buy 8 inch floppies for our computers on which to store our favorite programs and data. But, the manufacturing ability was not that good back then and 1% of these 8 inch floppies sold had a bad sector or two on them which made them have less memory ...
Thursday, July 10, 2014 at 12:14am

statistics
30 new babies were born yesterday in the hospital. If the average weight of a new born is 7.5 pounds with a standard deviation of 2.1 pounds, what is the probability of the average weight for these 30 newborns is between 7.2 and 7.6 pounds. Remember, all probabilities are ...
Thursday, July 10, 2014 at 12:14am

statistics
When using the normal approximation to the binomial, what is the standard deviation used in the standardization formula when approximating a binomial distribution with 226 trials and p=0.25? Please submit your answer with 4 decimal places
Thursday, July 10, 2014 at 12:14am

statistics
You have a box of 15 widgets whose average weight for each individual widget is 10 pounds with a standard deviation of 4.0 pounds. Based on this information, what is the standard deviation, taken to 4 decimal places, for the sample average of the weight of the widgets in the box?
Thursday, July 10, 2014 at 12:12am

statistics
When using the normal approximation to the binomial, what is the mean used in the standardization formula when approximating a binomial distribution with 123 trials and p=0.35? Please submit your answer with 2 decimal places
Thursday, July 10, 2014 at 12:12am

statistics
you have a box of 12 widgets whose average weight for each individual widget is 2.6 pounds with a standard deviation of 3.3 pounds. Based on this information, what is the mean, taken to 1 decimal place, for the sample average of the weight of the widgets in the box
Thursday, July 10, 2014 at 12:11am

statistics
Suppose that the ages of students at a particular university average 26 years with a standard deviation of 2.8 years. Consider the sampling distribution of the sample mean age of students in a sample of n = 49. The mean of the sampling distribution is __________
Wednesday, July 9, 2014 at 11:14pm

Statistics/Probability
The probability the New Year's day is on Saturday is a randomly chosen year is 1/7. 15 years was chosen randomly. Find the probability that, (1) Exactly four of these years have a New Year's day on a Saturday. (2) At least two of these years have New Year's day on ...
Wednesday, July 9, 2014 at 4:32pm

statistics, probability
It has been found out that the probability that a child is a male in family is 0.4. In a family of 6 children, what is the probability that; i. exactly 5 are boys ? ii. at least 4 are boys ? iii. all boys
Wednesday, July 9, 2014 at 6:06am

Statistics
The life of an electric light bulb is known to be normally distributed with a mean of 2000 hours and a std. of 120 hours. Find the probability that the life of such a bulb would be. (a) greater than 2150 hours (b) within the range of 1850 hours to 2090 hours
Tuesday, July 8, 2014 at 2:55pm

Math (statistics)
In an examination a candidate is given the four answers to four questions but is not told which answer applies to which question. He is asked to write down each of the four answers next to its appropriate question. b). show that there are 6 ways of getting just two answers in ...
Tuesday, July 8, 2014 at 11:21am

statistics
What formula do I use to solve: A sample with a mean of M = 40 and a variance of s2 = 20 has an estimated standard error of 2 points. How many scores are in the sample?
Tuesday, July 8, 2014 at 8:06am

statistics
A teacher wants to compare the mean geology scores of two different classes. She is testing the null hypothesis that there is no difference in the population mean scores of the two classes. The difference of the sample means is 51.4. If the standard deviation of the ...
Monday, July 7, 2014 at 11:01pm

Math/Statistics
A group of 10 students have average of GPA of 2.8 with SD of 0.3. Does this group present enough evidence to indicate that the average GPA is less than 3.0? Make your decision at a 5% level of significance.
Monday, July 7, 2014 at 6:29pm

Statistics
A group of 10 students have average of GPA of 2.8 with SD of 0.3. Does this group present enough evidence to indicate that the average GPA is less than 3.0? Make your decision at a 5% level of significance
Monday, July 7, 2014 at 5:27pm

statistics
Twelve different video games showing substance use were observed and the duration times of game play (in seconds) are listed below. The design of the study justifies the assumption that the sample can be treated as a simple random sample. Use the sample data to construct and ...
Monday, July 7, 2014 at 3:59pm

statistics
Could someone let me know if I did this correctly? Source Sum of Squares (degrees of freedom [df]) Mean Square Fobt. Fcrit. Gender 68.15 1.07 68.15/63.685 0.59 1.07,1,2 Marital Status 127.37 3.04 63.685/20.95 0.75 3.04,2,2 Gender * Marital Status (A x B) 41.90 2.28 20.95/9.2 0...
Monday, July 7, 2014 at 3:04pm

statistics
As a marketing promotion a company is going to give the first 200 customers a coupon for a discount when they enter the store. The customer cannot scratch off the coupon until they check out. the company orders 200 coupons and 150 are for 5% off, 30 are for 10% off, 15 are for...
Monday, July 7, 2014 at 1:27am

statistics
Describe one of the following experiments, which study human subjects, in 450 to 750 words: A pharmaceutical company wants to test a new sleep aid. An educational company is interested in determining whether their new math curriculum will raise standardized test scores. ...
Sunday, July 6, 2014 at 4:50pm

statistics
If you are told the mean grade in ECON 2023 is 80 with a standard deviation of 5, what is the probability that if you randomly selected 36 students you would find an average grade of 82 or more? I found the Z-score: 82-80/5 Which gave me .6554 then 1-.6554=.3446 So 34% would ...
Sunday, July 6, 2014 at 1:32pm

statistics
Blood type AB is found in only 3% of the population†. If 240 people are chosen at random, find the probability of the following. (Round your answers to four decimal places.) (a) 5 or more will have this blood type (b)between 5 an 10 will have this blood type
Saturday, July 5, 2014 at 9:10pm

Math
Statistics show that the sales force of a certain company successfully closed 296 sales out of 800 sales calls. What was their percent success rate?
Friday, July 4, 2014 at 5:55pm

Statistics
If a couple has 4 children and none are from multiple births or twins. With the probability of sons being 50% how many sons would they expect to have?
Friday, July 4, 2014 at 5:45pm

Statistics
The mean score on the first calculus exam was 55%. The standard deviation was 7%. Find the smallest interval about the mean that must contain at least 83% of the scores. heeellllppppp
Friday, July 4, 2014 at 3:50pm

statistics
At the start of December 2001, the retail price of a 25kg bag of cornmeal was $10 in Zambia, while by the end of the month, the price had fallen to $6. The result was that one retailer reported an increase in sales from 3 bags/day to 5 bags/day. Assume that the retailer is ...
Thursday, July 3, 2014 at 12:57am

statistics
in november 2008, apple stock dropped from $105 to $95 per share, and Microsoft dropped from $21 to $20 per share. If you invested a total of $3,570 in these stocks at the end of October and sold them for $3,250 at the end of November, how many shares of each stock did you buy?
Thursday, July 3, 2014 at 12:54am

statistics
help! where do i begin with this problem...in one area, monthly incomes of technology related workers have a standard deviation of $650. It is believed that the standard deviation of monthly incomes of non-technology workers is higher. A sample of 71 non technology workers are...
Tuesday, July 1, 2014 at 6:49pm

statistics
how much sale tax in due for a payment of 993.91
Tuesday, July 1, 2014 at 2:00pm

statistics
One of the ways most people relieve stress is to reward themselves with sweets. According to one study in Food Technology, 46 percent admit to overeating sweet foods when stressed. Suppose that the 46 percent figure is correct and that a random sample of 100 people is selected...
Tuesday, July 1, 2014 at 9:23am

Statistics
Compute the critical value za/2 that corresponds to a 85% level of confidence.
Monday, June 30, 2014 at 10:53pm

Statistics
An investor has $1400 to invest, and his financial analyst recommends two types of junk bonds. The A bonds have a 6% annual yield with a default rate of 3%. The B bonds have a 9% annual yield with a default rate of 7%. (If the bond defaults, the $1400 is lost.) Which of the ...
Monday, June 30, 2014 at 10:39pm

Statistics
A statistics professor plans classes so carefully that the lengths of her classes are uniformly distributed between 50.0 and 52.0 minutes. Find the probability that a given class period runs between 50.25 and 50.5 minutes.
Monday, June 30, 2014 at 10:34pm

Statistics
Many states are carefully considering steps that would help them collect sales taxes on items purchased through the Internet. How many randomly selected sales transactions must be surveyed to determine the percentage that transpired over the Internet? Assume that we want to be...
Monday, June 30, 2014 at 10:31pm

statistics
A Gallup poll of 1236 adults showed that 12% of the respondents believe that it is bad luck to walk under a ladder. Consider the probability that among 30 randomly selected people from 1236 who were polled, there are at least 2 who have that belief. Given that the subjects ...
Monday, June 30, 2014 at 10:21pm

Statistics
Find the critical value za/2 that corresponds to the given confidence level. 96%
Monday, June 30, 2014 at 10:17pm

Statistics
Assume that a procedure yields a binomial distribution with a trial repeated n times. Use the binomial probability formula to find the probability of x successes given the probability p of success on a single trial. n=21, x=18, p=0.75
Monday, June 30, 2014 at 9:59pm

Statistics
The distribution of IQ scores is a nonstandard normal distribution with a mean of 100 and a standard deviation of 15. What are the value of the mean and standard deviation after all IQ score have been standardized by converting them to z scores?
Monday, June 30, 2014 at 9:57pm

Statistics
Find the critical values x2L and x2R that correspond to the given confidence level and sample size. 99%: n=23
Monday, June 30, 2014 at 9:54pm

statistics
Assume that a procedure yields a binomial distribution with a trial repeated n times. Use a binomial probabilities table to find the probability of x successes given the probability p of success on a given trial. n=8, x=2, p=0.30
Monday, June 30, 2014 at 9:50pm

Statistics
A clinical trial tests a method designed to increase the probability of conceiving a girl. In the study 320 babies were born, and 256 of them were girls. Use the sample data to construct a 99% confidence interval estimate of the percentage of girls born. Based on the results, ...
Monday, June 30, 2014 at 9:47pm

statistics
simple randon sampling uses a sample size n
Monday, June 30, 2014 at 4:19pm

Statistics
An unbiased die is thrown seven times. Find the probability of throwing it at least five six's.
Monday, June 30, 2014 at 3:52pm

statistics
Select which of the following are examples of parameters from these examples. Question options: The probability that a ticket with be a winner is .2 (or a 20% chance) The proportion of winning tickets in the sample of 100 99% of samples will have between 37% and 43% of voters ...
Sunday, June 29, 2014 at 3:41pm

statistics
use SPSS to calculate the 90%, 95% and 99% confidence intervals for the mean of the variable weight. Interpret the three confidence intervals in terms of whether there is a significant difference between the mean of the sample and a hypothesized mean of 150.
Sunday, June 29, 2014 at 9:59am

statistics
The inside diameter of metal washers produced by a company are normally distributed with a mean of .5 inches and a standdrd deviation of .01 inches. Of all washers produced .8% of the washers are rejected because they are too small for a bolt used to test them. What is the ...
Saturday, June 28, 2014 at 1:31am

statistics
To find out what people think, the Gallup Poll selected a random sample of 520 women and 506 men. The pollsters showed them a list of personal attributes and asked them to indicate whether each attribute was “generally more true of men or of women”. When asked about ...
Friday, June 27, 2014 at 11:38pm

statistics
2. A researcher measures the heart rate in a population of runners and finds they have an average heart rate of µ = 50, σ = 5. You do not need to show a graph, only computation work. 2A. Based on the average heart rate cited above, what proportion would we expect to...
Friday, June 27, 2014 at 8:19pm

statistics
construct a 95% confidence interval estimate for the population mean MPG of 2010 family sedans, assuming a normal distribution.
Friday, June 27, 2014 at 5:57am

Statistics (Check Work)
Can Someone help me with these 2 problems? I am certain I am solving them correctly, but for some reason the computer keeps marking my answers as incorrect. Question 1: Minnesota had the highest turnout rate of any state for the 2012 Presidential election. Political analysts ...
Thursday, June 26, 2014 at 6:09pm

Statistics
1. In a study of heart disease in male federal employees, researchers classified 170 volunteer subjects according to their socioeconomic status (SES) and their smoking habits. SES categorized as high and low. Individuals were asked whether they were smokers or non-smoker. Here...
Thursday, June 26, 2014 at 2:34pm

statistics
A sample of 40 CDs from a student's collection showed a mean length of 52.74 minutes with a standard deviation of 13.21 minutes. Construct a 95% confidence interval for the population standard deviation. (Round your answers to 4 decimal places.)
Thursday, June 26, 2014 at 12:09am

statistics
Facebook reports that the average number of Facebook friends worldwide is 150 with a standard deviation of 90. If you were to take a sample of 25 students, what is the probability that the mean number Facebook friends in the sample will be 165 friends or more?
Tuesday, June 24, 2014 at 2:35pm

statistics
according to statistics, the maximum heart rate should be 220 minus a person's age. how would you interpret your highest rate in relation to that given?
Tuesday, June 24, 2014 at 8:09am

Statistics
No idea where to begin... Do men or women watch more T.V. per day? To answer the question two samples were select with the help of SPSS and the following results were produced. Is there a significant difference between men and women in watching T.V.? Perform five-step model to...
Sunday, June 22, 2014 at 12:55pm

Statistics
I'm taking stats online which is making it even more difficult for me and I have nowhere to begin when answering this question. 1. A pharmaceutical industry claimed that their new product will lower the cholesterol level by an average of 14.5. To verify the claim, a ...
Sunday, June 22, 2014 at 12:52pm

statistics
The following random sample was collected: 22 33 44 6. The 80% confidence interval for the mean is? I have the answers; however, I do not know how to plug in the numbers to solve the problem.
Saturday, June 21, 2014 at 11:44am

statistics
A researcher wishes to estimate the proportion of college students who cheat on exams. A poll of 490 college students showed that 33% of them had, or intended to, cheat on examinations. Find the margin of error for the 95% confidence interval. solution I have but what do I ...
Thursday, June 19, 2014 at 5:20pm

probability and statistics
Suppose every student in your class got a score of 85% on an exam. What are the mean and standard deviation of those exam scores without doing any calculations? I want to say the mean is 100 and the standard deviation is 1 but I don't know why. If all students scored 85% ...
Tuesday, June 17, 2014 at 9:30pm

Statistics
there is a 1/5 (.20) probability that one type of appliance will break with in two years. find the probability that 4 out 15 such appliances willl break within that time period
Tuesday, June 17, 2014 at 3:36pm

statistics
The true highway mileage, Y, of a specific brand of hybrid vehicle has a normal distribution with a mean of 42 and a standard deviation of 1.5. Find the probability that a randomly selected hybrid vehicle gets more than 38 miles to the gallon.
Tuesday, June 17, 2014 at 2:16am

Statistics
One of the questions in the Pew Internet & American Life Project asked adults if they used the Internet, at least occasionally. The results showed that 454 out of 478 adults aged 18 - 29 answered yes; 741 out of 833 adults aged 30 – 49 answered yes; 1058 out of 1644 ...
Monday, June 16, 2014 at 8:25pm

Statistics (Check Answer)
Hi can someone check my answer. I'm not sure why the computer keeps marking it wrong. **Suppose a random sample of size 50 is selected from a population with σ = 10. Find the value of the standard error of the mean in each of the following cases (use the finite ...
Monday, June 16, 2014 at 6:50pm

statistics for health research
1.A study is conducted to determine the factors that affect the increased maternal mortality rates in Kenya. Establish the variables (at least 5 variables) that you would use to conduct the study. State your expected results and explain how you will apply Correlation and ...
Monday, June 16, 2014 at 8:10am

statistics for health research
Descriptive statistics are widely used in qualitative research. When establishing if a population is normally distributed explain when the statistics of sample size, mean, mode, median, skewness and kurtosis will guide the researcher to make conclusions of a normal distribution.
Monday, June 16, 2014 at 8:06am

statistics for health research
the income of a group of 10,000 health system employees was found to be normally distributed with a mean=750 pm and standard deviation=50. show that of this group about 95% had income exceeding 668 and only 5% had income exceeding 832
Monday, June 16, 2014 at 8:03am

Statistics
Assume that a standardized test is designed to have the mean score of 100 and the standard deviation of 15. At the 95% confidence interval, how large does the sample size have to be if the margin of error is to be 3 points?
Sunday, June 15, 2014 at 8:28pm

statistics
A graph representing the distribution of the oral temperatures of 50 healthy adult males (selected at random) would best be described as?
Sunday, June 15, 2014 at 6:24pm

math statistics
In a survey of families in which both parents work, one of the questions asked was, "Have you refused a job, promotion, or transfer because it would mean less time with your family?" A total of 200 men and 200 women were asked this question. "Yes" was the ...
Saturday, June 14, 2014 at 6:23pm

Statistics
The complement of P(B | A) is 1 - P(B | A). Is it also true that 1 - P(B | A) = P(B' | A), where B' means the complement of B?
Friday, June 13, 2014 at 4:30am

Statistics
You have these 10 observations of some event X: 1.03 1.022 1.022 1.01 1.026 1.02 0.95 1.005 1.05 1.023 Here is the sorted list from least to greatest: 0.95 1.005 1.01 1.02 1.022 1.022 1.023 1.026 1.03 1.05 Based on this data alone: 1) It makes sense to say P(X <= 0.95) = 1/...
Thursday, June 12, 2014 at 10:57pm

statistics
Assume that a standardized test is designed to have the mean score of 100 and the standard deviation of 15. At the 95% confidence interval, how large does the sample size have to be if the margin of error is to be 3 points?
Thursday, June 12, 2014 at 4:39pm

Statistics
A research worker wishes to estimate the mean of a population by using sufficiently large sample. At the confidence level of 99%,the sample mean will be within 35% of the standard deviation. How large a sample should be taken?
Wednesday, June 11, 2014 at 6:48pm

Statistics
The mean cost of domestic airfares in the United States rose to an all-time high of $385 per ticket. Airfares were based on the total ticket value, which consisted of the price charged by the airlines plus any additional taxes and fees. Assume domestic airfares are normally ...
Wednesday, June 11, 2014 at 6:27pm

statistics
A politician claims that she will receive 65% of the vote in an upcoming election. The results of a properly designed random sample of 100 voters showed that 49 of those sampled will vote for her. Is it likely that her assertion is correct at the 0.05 level of significance? (a...
Wednesday, June 11, 2014 at 5:30pm

statistics
in a class of 100,84% of student have taken politics and 16% of the students have taken history. how many students have taken both subject of all the students take at least one these students?
Wednesday, June 11, 2014 at 4:41am

Statistics
Can someone please help me answer these questions? I have tried every method I know and the computer still keeps marking the answers as incorrect. Thanks for the help! 1) If the number of 18-34 year olds sampled is equal to the value identified in part "a"(value=157...
Tuesday, June 10, 2014 at 6:08pm

Statistics
How would you interpret the findings of a correlation study that reported a linear correlation of +0.3? I believe they have nothing in common because they are close to one. Please advise
Tuesday, June 10, 2014 at 2:39pm

math, statistics
The image of the public library is constantly changing, and their online services continue to grow. Usage of the library's home page grew by 17% during the past 12 months. It has been estimated that the current average length of a visit to the library's homepage is ...
Tuesday, June 10, 2014 at 11:18am

civics
statistics show that internet usage in the United states has grown from just 41 percent of households in 2000 to 77 present household in 2012. Which best describes how the internet has contributed to cultural diffusion in the United states? I'm stuck I don't even have ...
Tuesday, June 10, 2014 at 10:44am

statistics
For a normal distribution, explain why we calculate the probability of a range of numbers instead of the probability of a single number on the lines below?
Monday, June 9, 2014 at 6:51pm

statistics
What is the null hypothesis for the following questions: Is there a relationship between heart rate and the number of cups of coffee drunk within the last 4 hours?
Monday, June 9, 2014 at 6:33pm

statistics
An investigator wants to estimate caffeine consumption in high school students. How many students would be required to estimate the proportion of students who consume coffee? Suppose we want the estimate to be within 5% of the true proportion with 95% confidence. Alpha = ...
Sunday, June 8, 2014 at 7:26pm

Math statistics
How large a sample should be taken if the population mean is to be estimated with 95% confidence to within $69? The population has a standard deviation of $892. (Round you answer up to the nearest whole number.) You may need to use the appropriate table in Appendix B to answer...
Sunday, June 8, 2014 at 5:39pm

Math, statistics
A trucking firm delivers appliances for a large retail operation. The packages (or crates) have a mean weight of 306 lb. and a variance of 2209. (Give your answers correct to four decimal places.) (a) If a truck can carry 4070 lb. and 25 appliances need to be picked up, what ...
Sunday, June 8, 2014 at 9:08am

statistics
company A has 110 employed, company B has 750 employed and company C has 250 employed. Compute the probability that an employee selected at random comes from company A or B.
Saturday, June 7, 2014 at 2:48am

statistics
The outcome of a standardized test is an integer between 151 and 200, inclusive. The percentiles of 400 test scores are calculated, and the scores are divided into corresponding percentile groups. Quantity A Minimum number of integers between 151 and 200, inclusive, that ...
Saturday, June 7, 2014 at 2:09am

statistics
300 test results are integers ranging from 15 to 75, inclusive. Dominick’s result is clearly in the 80th percentile of those results, not the 79th or the 81st. Quantity A Number of other test results in the same percentile as Dominick’s Quantity B Maximum number of ...
Saturday, June 7, 2014 at 2:07am

statistics
solve: our health organization is interested in estimating the average value of outstanding accounts receivable. After selecting a sample of 100 accounts, suppose that the mean was $120 and the standard deviation was $40. Use these data to construct a 98% confidence interval. ...
Friday, June 6, 2014 at 10:37pm

Statistics
The life of a blood pressure monitor has a normal distribution with an average of 40 years and a standard deviation of one year. What should the warranty be to replace a malfunctioning monitor with - if the company does not want to replace more than 1% of all the monitor. ...
Friday, June 6, 2014 at 4:25pm

Statistics
The registration numbers of vehicles in a certain country use digits 1-999. If a visitor has just entered the country. What is the probability that the first car he sees has at least 2 identical digits? Ans: 29/111
Friday, June 6, 2014 at 9:28am

math
A sample of 64 statistics students at a small college had a mean mathematics ACT score of 28 with standard deviation of 4. Estimate the mean mathematics ACT score for all statistics students at college. Give the 95% confidence interval.
Thursday, June 5, 2014 at 8:27pm

statistics
What are the differences between hypothesis testing regarding population means drawn from small and large samples
Thursday, June 5, 2014 at 6:53pm

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