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April 18, 2014

April 18, 2014

**Recent Homework Questions About Statistics**

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**STATISTICS**

is it e or b?
*Saturday, August 10, 2013 at 11:39am*

**Statistics**

A study of generator related carbon monoxide deaths showed that a sample of 6 recent years had a variance of 16.8 deaths per year. Find the 99% confidence interval of the true variance
*Saturday, August 10, 2013 at 9:55am*

**Statistics**

not sure
*Saturday, August 10, 2013 at 9:49am*

**Statistics**

First one is the treatment has no effect
*Saturday, August 10, 2013 at 6:23am*

**statistics**

In a simple random sample of 250 father-son pairs taken from a large population of such pairs, the mean height of the fathers is 68.5 inches and the SD is 2.5 inches; the mean height of the sons is 69 inches and the SD is 3 inches; the correlation between the heights of the ...
*Saturday, August 10, 2013 at 3:26am*

**Statistics**

In a study of the effect of a medical treatment, a simple random sample of 300 of the 500 participating patients was assigned to the treatment group; the remaining patients formed the control group. When the patients were assessed at the end of the study, favorable outcomes ...
*Saturday, August 10, 2013 at 3:20am*

**Statistics**

Stat001 @Din123, well done
*Thursday, August 8, 2013 at 11:40pm*

**statistics**

Relative dispersion, sometimes called the coefficient of variation, is the result of dividing the st. dev. by the mean, hence it is dimensionless (it may also be presented as a percentage). So a low value of relative dispersion usually implies that the st. dev. is small in ...
*Thursday, August 8, 2013 at 9:35pm*

**Statistics**

A box contains 10 items, of which 3 are defective and 7 are non-defective. Two items are randomly selected, one at a time, with replacement, and x is the number of defective items in the sample. To look up the probability of a defective item being drawn from the box, using a ...
*Thursday, August 8, 2013 at 7:25pm*

**statistics**

A study of hours devoted to a graduate course outside of classroom time generates a mean score of 90 with a standard deviation of 20. The mean age of the students was 31 with a standard deviation of 5 years. What is the relative dispersion of the two data sets? A. 2.22%; 1.6% ...
*Thursday, August 8, 2013 at 3:05pm*

**Statistics**

Honor Code This can be found at edx org/honor and you are required to follow it. The course staff would like to express their appreciation of all the students who follow the honor code scrupulously. The honor code is not just decoration or boilerplate; it sets out community ...
*Wednesday, August 7, 2013 at 10:06pm*

**Statistics**

Why bother doing this class if you're just asking people to give you the answers? It's a free online class with no grades.
*Wednesday, August 7, 2013 at 7:14pm*

**STATISTICS**

Thank you MathGuru. This is what I was thinking about.. Sensitivity is the proportion of true positives that are correctly identified by the test. Specificity is the proportion of true negatives that are correctly identified by the test. Positive predictive value = the ...
*Wednesday, August 7, 2013 at 6:54pm*

**STATISTICS**

I don't think this can be determined from the information given. You would also have to know the prevalence of the disease in the population. Check this to be sure.
*Wednesday, August 7, 2013 at 6:46pm*

**STATISTICS**

A particular diagnostic test for disease X has a sensitivity of 90% and a specificity of 90%. What is the negative predictive value of the test? 90% 10% 1% 18% It cannot be determined from the information given.
*Wednesday, August 7, 2013 at 4:13pm*

**Statistics**

@Din123 Thank you
*Wednesday, August 7, 2013 at 2:11pm*

**Statistics**

@Helen - i can see that,not sure how the page was deleted,see below incl ur ans PROBLEM 1 ans: E & F PROBLEM 2 ans: C - "The distribution of the cholesterol levels of the residents of the state is close to normal, with an unknown mean and an unknown SD" PROBLEM 3 ans...
*Wednesday, August 7, 2013 at 2:10pm*

**Statistics**

A stationary store has decided to accept a large shipment of ball-point pens if an inspection of 20 randomly selected pens yields no more than two defective pens. a) find the probability that this shipment is accepted if 5% of the total shipment is defective. b) find the ...
*Wednesday, August 7, 2013 at 10:21am*

**Statistics**

PROBLEM 1 - "E" and "F"
*Wednesday, August 7, 2013 at 8:54am*

**STATISTICS**

Which of the following would increase the width of a confidence interval? Changing from a 99% to 95% confidence level. Increasing the variability of the outcome. Increasing the sample size. Removing an outlier from the data
*Wednesday, August 7, 2013 at 5:47am*

**STATISTICS**

A study examining the relationship between fetal X-ray exposure and a particular type of childhood blood cancer found the following odds ratio (and 95% confidence interval) for the association: 2.44 (0.95 to 6.33). This result would likely be considered: clinically significant...
*Wednesday, August 7, 2013 at 5:46am*

**STATISTICS**

You are performing a cohort study to look at risk factors for breast cancer in postmenopausal women. If the probability of developing breast cancer among smokers is .05 for the study duration, then if you sample 100 smokers, how many do you expect to develop the disease? Give ...
*Wednesday, August 7, 2013 at 5:45am*

**STATISTICS**

Thank you Lee!!
*Wednesday, August 7, 2013 at 5:43am*

**STATISTICS**

Oh now. I was right. You are wrong!
*Wednesday, August 7, 2013 at 5:43am*

**STATISTICS**

Thank you PsyDAG. I hope you had answer before.. I answered the B!
*Wednesday, August 7, 2013 at 5:42am*

**STATISTICS**

Thank you guys
*Wednesday, August 7, 2013 at 5:40am*

**Statistics**

Thank you stat001 The link you gave us is not directing on a specific question.
*Wednesday, August 7, 2013 at 5:38am*

**STATISTICS**

But it is wrong!
*Wednesday, August 7, 2013 at 5:32am*

**STATISTICS**

Thank you PsyDAG
*Wednesday, August 7, 2013 at 5:30am*

**STATISTICS**

79%
*Wednesday, August 7, 2013 at 1:14am*

**Writing**

This time I hope I improve. Writing is a skill that must be practiced. In order to be good at writing I must read a lot, right? I won't survive in college if I am not able to write superfluos essays,right????? *Thank you,Writeacher for your patience. I know you might be ...
*Wednesday, August 7, 2013 at 12:53am*

**STATISTICS (Partial)**

SEm = SD/√n
*Tuesday, August 6, 2013 at 10:25pm*

**STATISTICS**

If you don't know the right alternative, possibly you could find it by eliminating the false alternatives. Increased variability
*Tuesday, August 6, 2013 at 10:23pm*

**Statistics**

-If the null hypothesis were true, there would be about a 3% chance of getting data that were like those that were observed in the sample or even further in the direction of the alternative. -The P-value of about 3% was computed assuming that the null hypothesis was true
*Tuesday, August 6, 2013 at 9:00pm*

**Statistics**

have started another question forum with answers to make life easier...... jiskha com/display.cgi?id=1375826423 put a . b/w 1st two words.. site is not allowing me to post weblinks
*Tuesday, August 6, 2013 at 6:06pm*

**Statistics**

PROBLEM 4's ans is -2.5
*Tuesday, August 6, 2013 at 5:54pm*

**Statistics**

@helen- thank you.. @stat002- answer already posted as "The P-value of the test is closest to ans is 1.5% "
*Tuesday, August 6, 2013 at 5:43pm*

**Statistics**

P3 is 11
*Tuesday, August 6, 2013 at 5:06pm*

**STATISTICS**

You are performing a cohort study to look at risk factors for breast cancer in postmenopausal women. If the probability of developing breast cancer among smokers is .05 for the study duration, then if you sample 100 smokers, how many do you expect to develop the disease? Give ...
*Tuesday, August 6, 2013 at 3:57pm*

**STATISTICS**

A study examining the relationship between fetal X-ray exposure and a particular type of childhood blood cancer found the following odds ratio (and 95% confidence interval) for the association: 2.44 (0.95 to 6.33). This result would likely be considered: A) clinically ...
*Tuesday, August 6, 2013 at 3:57pm*

**STATISTICS**

Standard error: Is always the standard deviation divided by the square root of n. Is a measure of the variability of a sample statistic. Increases with bigger sample sizes. All of the above.
*Tuesday, August 6, 2013 at 3:54pm*

**STATISTICS**

Which of the following would increase the width of a confidence interval? Changing from a 99% to 95% confidence level. Increasing the variability of the outcome. Increasing the sample size. Removing an outlier from the data
*Tuesday, August 6, 2013 at 3:52pm*

**STATISTICS**

A study was conducted to examine the peer review process. The investigators hypothesized that reviewers suggested by authors would give more favorable reviews than reviewers picked by journal editors. They obtained data on 40 manuscripts that had been reviewed by 1 author-...
*Tuesday, August 6, 2013 at 3:50pm*

**STATISTICS**

In a survey of 1000 registered U.S. voters, 55% respond that they support health care reform. What is the 95% confidence interval for the true percentage of U.S. registered voters who support health care reform? 50%-60% 55%-60% 51%-59% 52%-58% 49%-47%
*Tuesday, August 6, 2013 at 3:48pm*

**STATISTICS**

The following table comes from a hypothetical case-control study that compared adults with moderate-to-severe acne (cases) to adults without acne (controls). The researchers examined the relationship between smoking and acne. The prevalence of moderate-to-severe acne in the ...
*Tuesday, August 6, 2013 at 3:48pm*

**STATISTICS**

Assume that the probability of developing lung cancer in smokers is 15%; the probability of developing lung cancer in non-smokers is 1%; and the prevalence of smokers in the U.S. is 20%. If a person is diagnosed with lung cancer, what is the probability that he/she is a smoker...
*Tuesday, August 6, 2013 at 3:46pm*

**STATISTICS**

In a cross-sectional study of heart disease and gender in middle-aged men and women, 10% of men in the sample had prevalent heart disease compared with only 5% of women in the sample. After adjusting for age in multivariate logistic regression, the odds ratio for heart disease...
*Tuesday, August 6, 2013 at 3:44pm*

**STATISTICS**

Researchers conducted a case-control study to identify risk factors for kidney cancer. They asked 50 cases and 50 controls about 100 different exposures and personal characteristics, and calculated the odds ratio for kidney cancer for each risk factor. They found statistically...
*Tuesday, August 6, 2013 at 3:43pm*

**STATISTICS**

In a psychology experiment in which 100 volunteers were asked to read a paragraph about an engineer, 65 assumed that the engineer was male despite the fact that the paragraph did not specify gender (and avoided gendered pronouns such as “he” or “she”). ...
*Tuesday, August 6, 2013 at 3:42pm*

**STATISTICS**

Researchers reported that in a sample of U.S. women aged 50 to 54 who underwent mammography, 14.4% were recalled for further evaluation; however, in a similar sample of women undergoing mammography in the United Kingdom, only 7.6% were recalled for further evaluation. What are...
*Tuesday, August 6, 2013 at 3:42pm*

**STATISTICS**

A particular diagnostic test for disease X has a sensitivity of 90% and a specificity of 90%. What is the negative predictive value of the test? 90% 10% 1% 18% It cannot be determined from the information given
*Tuesday, August 6, 2013 at 3:41pm*

**Statistics**

can anyone let me know the answer to PROBLEM 1 - A statistical test is performed, and its P-value turns out to be about 3%. Which of the following must be true? Pick all that are correct. PROBLEM 3 - The t distribution that should be used has ______ degrees of freedom. PROBLEM...
*Tuesday, August 6, 2013 at 3:41pm*

**Statistics**

Does anybody know the P4 and P5 answers? P4: -2.6 -2.1 and -2.3 are wrong P5: 1%, 2.5%, and 0.5% are wrong
*Tuesday, August 6, 2013 at 3:39pm*

**Statistics**

PROBLEM 8 ans is 1.8
*Tuesday, August 6, 2013 at 3:23pm*

**Statistics**

PROBLEM 9 ans is 3
*Tuesday, August 6, 2013 at 3:20pm*

**Statistics**

PROBLEM 7 ans is 14.5
*Tuesday, August 6, 2013 at 3:20pm*

**Statistics**

question number 10 ans is "one-sample z = (2.95 - 2.9)/0.055 = 0.909; P large; conclude chance variation"
*Tuesday, August 6, 2013 at 3:14pm*

**Statistics**

The P-value of the test is closest to ans is 1.5%
*Tuesday, August 6, 2013 at 3:12pm*

**Statistics**

Do not try the answers they tell you. We have many stupids here with psycho problems. They tell you randomly the answers to try for them!
*Tuesday, August 6, 2013 at 1:17pm*

**Statistics**

Need answer to P 10
*Tuesday, August 6, 2013 at 10:34am*

**Statistics**

Blossom's Flowers purchases roses for sale for Valentine's Day. The roses are purchased for $10 a dozen and are sold for $20 a dozen. Any roses not sold on Valentine's Day can be sold for $5 per dozen. The owner will purchase 1 of 3 amounts of roses for Valentine&#...
*Tuesday, August 6, 2013 at 10:27am*

**Statistics**

The questions 2, 3 and 4 are wrong
*Tuesday, August 6, 2013 at 8:16am*

**statistics**

On average, you receive four pieces of junk mail a day. For a randomsample of 10 weekends find the probability that at least 8 weekends youreceive exactly three pieces of junk mail?
*Tuesday, August 6, 2013 at 6:39am*

**Statistics**

What are the wrong answer?
*Monday, August 5, 2013 at 1:38pm*

**statistics**

http://www.google.com/search?client=safari&rls=en&q=type+i+and+type+ii+errors&ie=UTF-8&oe=UTF-8
*Monday, August 5, 2013 at 1:05pm*

**Statistics**

this test is easy listen the videos and do the exercises of those videos and it's easy. If you have any doubt just ask.
*Monday, August 5, 2013 at 12:45pm*

**Statistics**

Some answers are wrong.
*Monday, August 5, 2013 at 9:02am*

**statistics**

Identify the type I error and the type II error that is a hypothesis. The percentage of households with more than 1 pet is equal to 65%
*Sunday, August 4, 2013 at 7:37pm*

**Statistics**

QUESTION 1. The distribution of the cholesterol levels of the residents of the state is close to normal, with an unknown mean and an unknown SD. QUESTION 4 2% QUESTION 5 reject the null hypothesis QUESTION 2 2 QUESTION 3 -2.3
*Sunday, August 4, 2013 at 2:17pm*

**Statistics **

The distribution of cholesterol levels of the residents of a state closely follows the normal curve. Investigators want to test whether the mean cholesterol level of the residents is 200 mg/dL or lower. A simple random sample of 12 residents has a mean cholesterol level of 185...
*Sunday, August 4, 2013 at 11:23am*

**Statistics **

A statistical test is performed, and its P-value turns out to be about 3%. Which of the following must be true? Pick all that are correct. The null hypothesis is true. There is about a 3% chance that the null hypothesis is true. The alternative hypothesis is true. There is ...
*Sunday, August 4, 2013 at 11:19am*

**Statistics**

Mean=300*0.5=150 SD=SQRT(300*0.5*(1-0.5))=8.66 Z=+/- (170.5-150)/8.66 = +/- 2.37 Table of Z P= 2*0.0089 = 1.78% +/- because we have two-tailed and multiple the value of P by 2 for the same reason
*Sunday, August 4, 2013 at 5:33am*

**Statistics**

2.33 84.13
*Saturday, August 3, 2013 at 5:14pm*

**Statistics**

Hola ¿Cuál es el P - value en este problema que escribiste?
*Saturday, August 3, 2013 at 11:58am*

**Statistics**

Hi CC, Thanks for the ans. I also want to know how to calculate this value? How did u get 1.78? Once again thanks for the ans.
*Saturday, August 3, 2013 at 6:55am*

**Statistics**

Hey :) could you please tell me how did you get the answer 1.78 ??? I want to know how to calculate it. Thanks a lot for your help!
*Saturday, August 3, 2013 at 5:59am*

**statistics**

There are two boxes, each with several million tickets marked “1” or “0”. The two boxes have the same number of tickets, but in one of the boxes, 49% of the tickets are marked “1” and in the other box 50.5% of the tickets are marked “1”...
*Friday, August 2, 2013 at 6:40pm*

**Statistics**

thanks :) had achieved good luck to the course excuse the English'm from Portugal
*Friday, August 2, 2013 at 6:12pm*

**statistics**

Archie must travel to a foreign country where a deadly strain of flu has ravaged the population. Already, 34% of the population has succumbed to the flu and died. There is a vaccine, but because the flu is extremely contagious, it spreads quite rapidly, and to date only 1 out ...
*Friday, August 2, 2013 at 6:06pm*

**english**

If you go to the Internet and do a research for statistics to back up your argument for a speech you are writing for your Communications class, it is considered: A. primary research. B. investigative research. C. systematic research. D. secondary research.
*Friday, August 2, 2013 at 4:57pm*

**Math Statistics**

Suppose a large-scale randomized experiment were conducted to compare two weight loss plans. At the end of the experiment, the weight loss for each subject (in pounds) was recorded. The p-value turned out to be .004, and a 99% confidence interval for the difference in means ...
*Friday, August 2, 2013 at 1:51pm*

**Statistics**

To CC, 2 is B, 6 is B
*Friday, August 2, 2013 at 12:34pm*

**Statistics**

you know the correct answer to the problem 2 and 6 of the test? The P-value (problem 8) is 1.78 (it is correct)
*Friday, August 2, 2013 at 9:58am*

**Statistics**

Thanks youre right bud!
*Friday, August 2, 2013 at 5:56am*

**Statistics**

A statistics student hands each of 300 classmates 2 cookies side by side on a plate. Of the 300 students, 171 choose the cookie that’s on their right hand side, and the remaining 129 choose the cookie that’s on their left. The student says, “That’s just ...
*Friday, August 2, 2013 at 4:52am*

**statistics**

Yes there is enough evidence to support---- T = (16-15.6)/(.3/sqrt(8)) df = n-1 df = 8-1 = 7 critical t value = 1.895
*Friday, August 2, 2013 at 1:32am*

**statistics**

Yes there is enough evidence to support---- T = (16-15.6)/(.3/sqrt(8)) df = n-1 df = 8-1 = 7 critical t value = 1.895
*Friday, August 2, 2013 at 1:31am*

**statistics**

A machine is designed to fill jars with 16 ounces of coffee. A consumer suspects that the machine is not filling the jars completely. A sample of 8 jars has a mean of 15.6 ounces and a standard deviation of 0.3 ounce. Is there enough evidence to support the consumer's ...
*Friday, August 2, 2013 at 12:44am*

**statistics**

Suppose a large-scale randomized experiment were conducted to compare two weight loss plans. At the end of the experiment, the weight loss for each subject (in pounds) was recorded. The p-value turned out to be .004, and a 99% confidence interval for the difference in means ...
*Thursday, August 1, 2013 at 10:41pm*

**Statistics**

There are two boxes, each with several million tickets marked “1” or “0”. The two boxes have the same number of tickets, but in one of the boxes, 49% of the tickets are marked “1” and in the other box 50.5% of the tickets are marked “1...
*Thursday, August 1, 2013 at 1:21pm*

**Statistics**

I think it will be 1,78% then confirm if that was the correct answer
*Thursday, August 1, 2013 at 11:06am*

**Statistics**

why D?
*Thursday, August 1, 2013 at 10:14am*

**Statistics**

no its D
*Thursday, August 1, 2013 at 9:37am*

**statistics**

A sample of 100 iron bars is said to be drawn from a large number of bars. Whose lengths are normally distributed with mean 4 feet and S.D 0.6ft. If the sample mean is 4.2 ft, can the sample be regarded as a truly random sample?
*Thursday, August 1, 2013 at 9:37am*

**Statistics**

I would say the alternate hypothesis is rejected
*Thursday, August 1, 2013 at 6:46am*

**Statistics**

4257/5352
*Thursday, August 1, 2013 at 4:23am*

**statistics**

448/450
*Thursday, August 1, 2013 at 4:22am*

**Statistics**

A statistics student hands each of 300 classmates 2 cookies side by side on a plate. Of the 300 students, 171 choose the cookie that’s on their right hand side, and the remaining 129 choose the cookie that’s on their left. The student says, “That’s just ...
*Thursday, August 1, 2013 at 2:25am*

**statistics**

After one month of operation the health information services at community health center determined that there were two reords misfiled out of the 450 active records. What is the filing accuracy rate for this area?
*Thursday, August 1, 2013 at 12:28am*

**Statistics**

after one month of operation the health information services at community health center determined that there were two records misfiled out of the 450 active records. what is the filing accuracy rate for this area?
*Thursday, August 1, 2013 at 12:22am*

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