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August 22, 2014

Homework Help: Math: Statistics

Recent Homework Questions About Statistics

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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

STATISTICS
Suppose that you are in a class of 29 students and it is assumed that approximately 16% of the population is left-handed. (Give your answers correct to three decimal places.) (a) Compute the probability that exactly five students are left-handed. (b) Compute the probability ...
Thursday, June 5, 2014 at 11:10am

statistics
suppose you roll two number cubes and pick a letter of the alphabet at random. find the probability you will roll two odd numbers and pick one of the letters k, l, or m.
Wednesday, June 4, 2014 at 10:55pm

statistics
The diameter of an electric cable is normally distributed, with a mean of 0.6 inch and a standard deviation of 0.02 inch. What is the probability that the diameter will exceed 0.62 inch? (You may need to use the standard normal distribution table.
Wednesday, June 4, 2014 at 4:20pm

statistics
Draw a stem-and-leaf plot for the data set. (Enter numbers from smallest to largest separated by spaces. Enter NONE for stems with no values.) 60 14 24 35 22 37 14 23 19 33 15 16 50
Tuesday, June 3, 2014 at 5:29pm

statistics
the breaking strength (in pounds) of a certain new synthetic is normally distributed, with a mean of 125 and a variance of 25. The material is considered defective if the breaking strength is less than 113 pounds. What is the probability that a single, randomly selected piece ...
Tuesday, June 3, 2014 at 5:27pm

statistics
the breaking strength (in pounds) of a certain new synthetic is normally distributed, with a mean of 125 and a variance of 25. The material is considered defective if the breaking strength is less than 113 pounds. What is the probability that a single, randomly selected piece ...
Tuesday, June 3, 2014 at 5:27pm

statistics
Between 50 and 80 people are hired on a ship. 75% speak English only and 25% speak German only. What is the mean number of people that speak English only? Can this even be calculated?
Tuesday, June 3, 2014 at 11:28am

statistics
In how many ways can 24 identical white ball and 19 black ball be arranged in rows so that no black balls are together.
Tuesday, June 3, 2014 at 10:19am

statistics
In a class of 100 ,84% of the students have taken politics &16% of student have taken history.how many students have taken both subject of all the students take at least one of these subjects?
Tuesday, June 3, 2014 at 10:17am

statistics
An 8th grade history teached studied the statistics for her mid-term exam. The average grade for the mid-term was 84 points, and the standard deviation was 8 points. The Z-score for a student who scores 90 on the exam is: 84-90/8= -0.75
Tuesday, June 3, 2014 at 7:36am

statistics
Give the probability in decimal form (correct to two decimal places). A calculator may be helpful. Last semester, a certain professor gave 35 As out of 259 grades. If one of the professor's students from last semester were selected randomly, what is the probability that ...
Sunday, June 1, 2014 at 9:48pm

Statistics/I am confused
The breaking strength (in pounds) of a certain new synthetic is normally distributed, with a mean of 115 and a variance of 25. The material is considered defective if the breaking strength is less than 105 pounds. What is the probability that a single, randomly selected piece ...
Saturday, May 31, 2014 at 10:43pm

statistics
A sample of n= 4 scores has SS equals 48 what is the estimated standard error for the sample mean
Saturday, May 31, 2014 at 6:29pm

Statistics
A class obtained the following scores on a test. Test Score TestScore Frequency 90 1 80 6 70 10 60 3 50 2 40 3 What I did was 90+6(80)+7(10)+3(60)+2(50)+3(40)=1040 than divided by 25 which should give me the means it give me a fraction, I got the median right 70,mode right 70...
Saturday, May 31, 2014 at 6:08pm

Statistics/ is this how I do it.
Find the range and the standard deviation (correct to two decimal places). 83,96,100,100,103 find the range and standard deviation Do I that 5 numbers add that divide by 5 for the range I am not sure how to do standard deviation. Thank you
Saturday, May 31, 2014 at 4:28pm

Statistics 1
If light bulbs are normally distributed with a mean of 2500 hrs. and a standard deviation of 500 hrs. what percentage of light bulbs have a life span less than 2500 hrs.?
Friday, May 30, 2014 at 11:14pm

statistics
Can someone please help me understand how confidence intervals fit within the broader context of inferential statistics
Thursday, May 29, 2014 at 9:02pm

statistics
A researcher is measuring air quality samples. The average air quality of his samples is 60 clean units. If a raw score of a clean in a specific hospital room is 75 and the corresponding z-score is 5, what is the standard deviation of the dataset?
Thursday, May 29, 2014 at 3:10pm

statistics
A researcher finds that the correlation between variable A and variable B is r = +.20. She also finds that the correlation between variable C and variable B is r = -.40. Which relationship is scientifically more useful and by how much?
Thursday, May 29, 2014 at 1:35pm

statistics
in a positive skewed distrubtion with a mean (average) of 100 and median of 90 is What?
Thursday, May 29, 2014 at 10:50am

statistics
The diameter of an electric cable is normally distributed, with a mean of 0.8 inch and a standard deviation of 0.03 inch. What is the probability that the diameter will exceed 0.83 inch? (You may need to use the standard normal distribution table. Round your answer to three ...
Thursday, May 29, 2014 at 12:07am

statistics
An average of 1.4 private airplanes arrive per hour at an airport. Let x denote the number of private airplanes that will arrive at this airport during a given hour. Calculate the probability distribution of x. Find the probability that x = 4.
Wednesday, May 28, 2014 at 4:44pm

statistics
A company director took a sample of salaries of 13 employees in a big school during a certain time. she divided the wages into three groups according to the different jobs: teachers, assistants and coordinators as displayed in the table below. She wanted to find out whether or...
Tuesday, May 27, 2014 at 11:04am

statistics
Fill in the blank in the sample below if the variables are independent in the sample like product do not like product old 10 7 young 40
Sunday, May 25, 2014 at 12:19am

statistics
what is the relationship between hypothesis testing, statistical significance, and Type I and II errors
Saturday, May 24, 2014 at 10:24pm

Statistics
1. This probability distribution shown below relates to the number of times a person goes to a local coffee shop per day. What is the expected mean (average) number of times a person goes to a local coffee shop per day? 2. What is the area equal to under a normal curve ...
Friday, May 23, 2014 at 11:29am

Statistics
A hotel chain is interested in evaluating processes. Guests can reserve a room by using either a telephone system or an online system that is accessed through the hotel's web site. Independent random samples of 80 guests who reserved a room by phone and 60 guests who ...
Friday, May 23, 2014 at 1:01am

Statistics
A survey of 1,000 adult Americans included the following question: "If the military draft were reinstated, would you favor or oppose drafting women as well as men?" Forty-three percent responded that they would favor drafting women if the draft were reinstated. Using...
Friday, May 23, 2014 at 12:46am

Statistics
Suppose the mean income of 35-year-olds in the US is $25,000. A random sample of 150 35-year-olds in California results in a sample mean income of $26,600 and a sample standard deviation of $3800. At the 5% significance level, ca we conclude that the true mean income of 35-...
Friday, May 23, 2014 at 12:29am

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