Friday
April 18, 2014

Homework Help: Math: Statistics

Recent Homework Questions About Statistics

Post a New Question | Current Questions

math
Z = (mean1 - mean2)/standard error (SE) of difference between means SEdiff = √(SEmean1^2 + SEmean2^2) SEm = SD/√n If only one SD is provided, you can use just that to determine SEdiff. Find table in the back of your statistics text labeled something like "...
Saturday, November 30, 2013 at 4:26pm

statistics
what test are you using? This is very confusing!
Saturday, November 30, 2013 at 1:20pm

statistics
Z = (mean1 - mean2)/standard error (SE) of difference between means SEdiff = √(SEmean1^2 + SEmean2^2) SEm = SD/√n (n = # of trips) If only one SD is provided, you can use just that to determine SEdiff. Find table in the back of your statistics text labeled ...
Saturday, November 30, 2013 at 12:53pm

statistics
Ala rge fleet of cars is maintained with an average of 26 mpg. 50 recent trips displayed a mean of 25.02 mpg and standard deviation of 4.1 mpg. At the 5% level of significance, is their evidence the company has failed to keep their fuel goals? I did the math and got .03380315...
Saturday, November 30, 2013 at 12:27pm

Statistics
a
Saturday, November 30, 2013 at 10:23am

Probability and Statistics
The proportion of adults living in a small town who are college graduates is estimated to be p = 0.6. To test this hypothesis, a random sample of 15 adults is selected. If the number of college graduates in the sample is anywhere from 6 to 12, we shall not reject the null ...
Saturday, November 30, 2013 at 1:50am

Statistics
Thank you, I got the same answer, but I thought that because the sample size was less than 30, there was something I missed.
Friday, November 29, 2013 at 11:30pm

Statistics
mean = $115 Sd = $25 n = 15 1-a = .92 a = 0.08 Za/2 = z.04 = 1.75 115 -+ 1.75 * 25/sqrt15)) 115-+ 11.296 (103.704, 126.296)
Friday, November 29, 2013 at 11:25pm

Statistics
I have two coins: a quarter and a nickel. The quarter has a bias of 1/4 for heads, and the nickel has a bias of 2/3 for heads. I flip each coin 10 times. What is the probability that I observe exactly five heads total? Some explanation of the solution would be appreciated.
Friday, November 29, 2013 at 11:04pm

Statistics
Hello, my problem is I have a random sample of only 15 sales average is $115 with a known population standard deviation of $25.00. Obtain a 92% confidence interval and explain what your answer means. I am not sure what to do because the sample size is only 15. Thanks for your ...
Friday, November 29, 2013 at 8:00pm

Probability and Statistics
The proportion of adults living in a small town who are college graduates is estimated to be p = 0.6. To test this hypothesis, a random sample of 15 adults is selected. If the number of college graduates in the sample is anywhere from 6 to 12, we shall not reject the null ...
Friday, November 29, 2013 at 7:30pm

statistics
raw numbers
Friday, November 29, 2013 at 8:55am

statistics
In a distribution of sentence lengths in months like the following: 6, 12, 10, 18, 24, 360; which statistic would a researcher not want to report? a. standard deviation b. mean c. range d. raw numbers
Friday, November 29, 2013 at 8:13am

Probability and Statistics
The proportion of adults living in a small town who are college graduates is estimated to be p = 0.6. To test this hypothesis, a random sample of 15 adults is selected. If the number of college graduates in the sample is anywhere from 6 to 12, we shall not reject the null ...
Thursday, November 28, 2013 at 5:13pm

Probability and Statistics
The proportion of adults living in a small town who are college graduates is estimated to be p = 0.6. To test this hypothesis, a random sample of 15 adults is selected. If the number of college graduates in the sample is anywhere from 6 to 12, we shall not reject the null ...
Wednesday, November 27, 2013 at 11:34pm

Statistics
KE$HA IS A CELEB. I LOVE HER I LOV EHER KE$HIE IS A CELEB I LOVE HER_♥__♥_____♥__♥​;___ Put This _♥_____♥_♥_____♥​__ Heart _♥______♥______♥__ On Your __♥_____/______♥__ Page If ___♥...
Wednesday, November 27, 2013 at 1:14pm

Math
I'm currently taking IBMS and it has elements of several types of math classes (calculus, statistics, algebra, etc.). It is the "lowest" level IB Math class one can take, but not necessarily for students who have a low background in math. I know one student who ...
Wednesday, November 27, 2013 at 10:45am

Statistics
well, since 51.75 is 57.5% of the way between 46 and 56, ...
Wednesday, November 27, 2013 at 6:05am

Statistics
A statistics professor plans her classes so carefully that the lengths of her class are uniformly distributed between 46.0 and 56.0 minutes. Find the probablity that given class period runs less than 51.75 minutes
Wednesday, November 27, 2013 at 3:47am

Statistics
a. Ho: p = 0.5 Ha: p > 0.5 b) z = 2.41 c) p-value = 0.0080 d) reject the Ho; there is sufficient evidence to claim that the probability of a baby being a girl is greater than 0.5
Tuesday, November 26, 2013 at 6:27pm

Statistics
A clinical trial tests a method designed to increase the probability of conceiving a girl. In the study, 449 babies were born, and 250 of them were girls. Use the sample data with .01 significance level to test the claim that with this method, the probability of a baby being a...
Tuesday, November 26, 2013 at 6:03pm

statistics
A few hints: If you use the normal distribution as an approximation, then you will need to find the mean and standard deviation. mean = np = 13 * 0.7 = 9.1 standard deviation = √npq = √(13)(0.7)(0.3) = 1.65 (rounded) Note: q = 1 - p Next step: use z-scores z = (x...
Tuesday, November 26, 2013 at 4:41pm

statistics
The result is a statistic because it describes some characteristics of a sample. Or is it because if describes some characteristics of a population? this is where I get confused. thanks
Tuesday, November 26, 2013 at 1:37pm

statistics
A parameter is data about the whole population, while a statistic deals with a part of the population, a sample. What does that tell you?
Tuesday, November 26, 2013 at 1:16pm

statistics
A particular country has 55 total states. If the areas of 30 states are added and the sum is divided by 30, the result is 196,582 square kilometers. Determine whether this result is a statistic or a parameter and why.
Tuesday, November 26, 2013 at 1:02pm

statistics
With n=13 and p= 0.7, find the binomial probability p(9) by using a binomial probability table. If np> and nq> 5, also estimate the indicated probability by using the normal distribution as an approximation to the binomial, if np<5 or nq<5 then state that the ...
Monday, November 25, 2013 at 9:36pm

statistics
See your other post.
Monday, November 25, 2013 at 7:24pm

statistics
Outliers in a box plot may be evidence of a non-normal distribution, but this might not always be the case. If the box plot has symmetry around the median, the distribution will most likely be normal.
Monday, November 25, 2013 at 7:23pm

Statistics
It may be due to the sample size. There is a possibility the sample may be too large, which will affect the significance of the outcome.
Monday, November 25, 2013 at 6:51pm

statistics
You can try a proportional one-sample z-test for this one since this problem is using proportions. Here's a few hints to get you started: Null hypothesis: Ho: p = .5 -->meaning: population proportion is equal to .5 Alternative hypothesis: Ha: p > .5 -->meaning: ...
Monday, November 25, 2013 at 6:36pm

statistics
If you need to show the work by hand, you can develop the regression equation in the following format: predicted y = a + bx ...where a represents the y-intercept and b the slope. To get to that point, here are some formulas to calculate along the way. To find a: a = (Ey/n) - b...
Monday, November 25, 2013 at 6:25pm

Statistics
If you perform a statistical test, try a one-sample z-test. z = (sample mean - population mean)/(standard deviation divided by the square root of the sample size) Population mean = 80 Sample mean = ? (I don't see one listed) Standard deviation = 10.15 Sample size = 50 Once...
Monday, November 25, 2013 at 6:19pm

Statistics
An industrial psychologist has a stress test that is used to determine the amount of stress that managers are under. A value of 80 or higher indicates “high stress.” The industrial psychologist believes that the managers at a large, profitable pharmaceutical firm are...
Monday, November 25, 2013 at 5:22pm

statistics
In a study of caffeine and stress, college students indicate how many cups of coffee they drink per day and their stress level on a scale of 1-10. The data appear below. Number of Cups of Coffee Stress Level 3 5 2 3 4 3 6 9 5 4 1 2 7 10 3 5 = 3.88 X= 5.13 s = 2.03 s = 2.90 ...
Monday, November 25, 2013 at 3:36pm

statistics
right.
Monday, November 25, 2013 at 1:26pm

Statistics
% = mean ± Z(SEm) Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion/probability (%/2) from the mean and its Z score. Substitute values into above equation and calculate. If you ...
Monday, November 25, 2013 at 1:23pm

statistics
A normal distribution approximates a bell-shaped curve. Outliers to one side would skew the distribution. If the distribution was flat, having about the same frequencies throughout the distribution, this would be non-normal. Also a bimodal distribution would be non-normal, ...
Monday, November 25, 2013 at 1:17pm

statistics psy/315
Z = (mean1 - mean2)/standard error (SE) of difference between means SEdiff = √(SEmean1^2 + SEmean2^2) SEm = SD/√n If only one SD is provided, you can use just that to determine SEdiff. Find table in the back of your statistics text labeled something like "...
Monday, November 25, 2013 at 1:02pm

statistics psy/315
Based on the information given for each of the following studies, decide whether to reject the null hypothesis.For each, give (a) the Z-score cutoff (or cutoffs) on the comparison distribution at which the null hypothesis should be rejected(b) the Z score on the comparison ...
Monday, November 25, 2013 at 11:12am

statistics
A clinical trial tests a method designed to increase the probability of conceiving a girl. In a study 306 babies were born, and 174 of them were girls. the sample data with a 0.01 significance level to test the claim that with this method, the probability of being a girl is ...
Monday, November 25, 2013 at 10:25am

Statistics
n two separate studies, the actual difference between the means of a treated group and an untreated group is 3 points. However, in one study, the σM1-M2 is very large and so the 3 points is not found to be significant. In the other study, the σM1-M2 is ...
Monday, November 25, 2013 at 7:18am

Statistics
(1.96*2.5)/0.25)^2=384.16 that's right or wrong?? i'm not understand why the population standard deviation round up to 3?? anyone help? this for question post by shyra..
Monday, November 25, 2013 at 1:27am

statistics
how would you tell deviations from normality by looking at a box plot?
Sunday, November 24, 2013 at 7:11pm

statistics
how would you tell deviations from normality by looking at a box plot?
Sunday, November 24, 2013 at 7:08pm

statistics
what makes a probability plot non-normal? I would think outliers are one of them, but what else?
Sunday, November 24, 2013 at 7:06pm

Statistics
Given the following information, determine the 68.3 percent, 95.5 percent, and 99.7 percent confidence intervals. overbar above X equals 4.33 comma SE sub m equals 3 I would appreciate it extremely if someone would help me figure this out. I honestly have no idea how to do ...
Sunday, November 24, 2013 at 6:33pm

statistics
I think I have it...nevermind .94 on z chart =1.55...then multiply 1.55 times error (10) then time 60=75.5?
Sunday, November 24, 2013 at 5:26pm

statistics
Typing speeds among college students are normally distributed with a mean of 60 words, and a standard deviation of 10 words. determine the typing speed that separates the top 6% typists from the rest.
Sunday, November 24, 2013 at 3:55pm

statistics
1. A professor measured the time (in seconds) required to catch a falling meter stick for 19 randomly selected students’ dominant and non-dominant hand. The professor claims that the reaction time in an individual’s dominant hand is less than the reaction time in ...
Sunday, November 24, 2013 at 3:33pm

Statistics
I get it now...I was missing a step too! Thanks Much!
Sunday, November 24, 2013 at 3:23pm

Statistics
YES. IF YOUR PROFESSOR SAID THAT YOUR ANSWER SHOULD BE IN PERCENT. P = 142/507 = 0.28 SD = SQRT( .28*.72/507) SQRT(0.2016/507) = 0.0199 1-a = .95 a =0.05 za/2 = z0.025 = 1.96 Z = 1.96 p -+ za/2 * SD/sqrt(n) 0.28-+1.96*0.0199 0.28-+ 0.039 ( 0.241, 0.319) IF YOUR PROFESSOR SAID...
Sunday, November 24, 2013 at 3:22pm

Statistics
YES. IF YOUR PROFESSOR SAID THAT YOUR ANSWER SHOULD BE IN PERCENT. P = 142/507 = 0.28 SD = SQRT( .28*.72/507) SQRT(0.2016/507) = 0.0199 Z = 1.96 0.28-+1.96*0.0199 0.28-+ 0.039 ( 0.241, 0.319)
Sunday, November 24, 2013 at 3:13pm

Statistics
142 out of 507 people were right. Calculate a 95% confidence interval for the proportion of the entire population that could be right. I did some of the work …Please help. I am getting .0199 SD =sqt(.28(1-.28)/506 = .0119 so .28 +/- .0119 so I could say that with 95% ...
Sunday, November 24, 2013 at 3:08pm

Statistics
you know I am getting .0199 SD =srt(.28(1-.28)/506 = .0119? Please check for me again?
Sunday, November 24, 2013 at 2:56pm

Statistics
so I could say that with 95% confidence, between 24.1% and 31.9% of the entire population could be right?
Sunday, November 24, 2013 at 2:27pm

statistics (?)
What following? Z = (score-mean)/SD Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion/probability related to the Z score. This may help you decide.
Sunday, November 24, 2013 at 2:04pm

Statistics
p = 142/ 507 = 0.28 SD = sqrt(p(1-p)/n) 0.28-+ 0.039 (.241, .319)
Sunday, November 24, 2013 at 2:00pm

Statistics
a) 1.409 b) ( -2.822, 5.64) c) 4.23
Sunday, November 24, 2013 at 1:52pm

Statistics
142 out of 507 people were right. Calculate a 95% confidence interval for the proportion of the entire population that could be right. I did some of the work and got .72...don't know what to do with this? Please help.
Sunday, November 24, 2013 at 1:45pm

Statistics
A sample of 11 observations taken from a normally distributed population produced the following data. −7.1 10.3 8.7 −3.6 −6.0 −7.5 5.2 3.7 9.8 −4.4 6.4 a) What is the point estimate of μ? b) Make a 95% confidence interval for μ. c) What ...
Sunday, November 24, 2013 at 12:25pm

Statistics
Many dairy cows now receive injections of BST, a hormone intended to spur greater milk production. A group of 53 Jersey cows increased average milk production from 43 to 52 pounds per day, with a standard deviation of 4.8 lbs. Is this evidence that the hormone maybe effective ...
Sunday, November 24, 2013 at 9:14am

statistics
For the past 20 years, the high temperature on April 15th has averaged  = 62 degrees with a standard deviation of  = 12. Last year, the high temperature was 68 degrees. Based on this information, which of the following best describes last year's temperature...
Sunday, November 24, 2013 at 2:42am

Statistics
Margin of error = 0.02 z = 2.58 Unknown p We are going use 50% n = (za/2 /E ) ^2 *p(1-p) n = (2.58/0.02)^2*.5* .5 = 4160.25 n = 4161
Saturday, November 23, 2013 at 7:16pm

Statistics
Margin of error = 0.02 z = 2.58 Unknown p We are going use 50% n = (za/2 /E ) ^2 *p(1-p) n = (2.58/0.02)^2*.5* .5 = 4160.25 n = 4161
Saturday, November 23, 2013 at 7:16pm

Statistics
This is not correct
Saturday, November 23, 2013 at 6:41pm

Statistics
4065
Saturday, November 23, 2013 at 6:13pm

Statistics
Exercise 8.92 Tony's Pizza guarantees all pizza deliveries within 30 minutes of the placement of orders. An agency wants to estimate the proportion of all pizzas delivered within 30 minutes by Tony's. What is the most conservative estimate of the sample size that would...
Saturday, November 23, 2013 at 6:10pm

Statistics
Tony's Pizza guarantees all pizza deliveries within 30 minutes of the placement of orders. An agency wants to estimate the proportion of all pizzas delivered within 30 minutes by Tony's. What is the most conservative estimate of the sample size that would limit the ...
Saturday, November 23, 2013 at 6:08pm

statistics
10.9 - +2.575 *6.2/√300 10-+ 0.9217 = (9.98, 11.82)
Saturday, November 23, 2013 at 4:06pm

Statistics
Use. Population proportion Ho: p = 0.2 Ha: p > 0.2 if P-value is greater than significance level fail to reject Ho: if P-value is less than significance level Reject Ho. z = 2.80 p-value = p ( z > 2.8) = 0.003 Reject the null hypothesis. There is sufficient evidence ...
Saturday, November 23, 2013 at 3:59pm

statistics
If the average commute time is 10.9 miles, but the average is actually the mean of a sample of 300 commuters and the sample standard deviation is 6.2 miles Estimate the true mean commute distance using 99% confidence level.
Saturday, November 23, 2013 at 3:00pm

Statistics
125/500 women soda drinkers indicate they drink diet soda. At the .01 level, does this evidence indicate that more than 20% of the women soda drinkers drink diet soda? Determine and explain the P-value please. I have the numbers...just cannot explain. Please help.
Saturday, November 23, 2013 at 2:51pm

statistics
Cannot sketch on these posts. Z = (score-mean)/SD Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportions/probabilities related to the Z scores.
Saturday, November 23, 2013 at 12:57pm

statistics
Type I: rejecting Ho when it is true Type II: failure to reject Ho when it is false answer is false
Saturday, November 23, 2013 at 11:01am

statistics
Failing to reject the null hypothesis when it is false is a Type II Error. T or F, and why or why not?
Saturday, November 23, 2013 at 10:30am

statistics
IQ scores were obtained from randomly selected couples.For 20 such pairs of people, the linear correlation coefficient is 0.881 and the equation of the regression line is y= -6.93+ 10.8x, where x represents the IQ score of the husband. Also, the 20x values have a mean of 105....
Saturday, November 23, 2013 at 8:42am

statistics
Assume that thermometer readings are normally distributed with a mean of 0.0 and a standard deviation of 1,00. the thermometer is randomly selected and tested. For the case below, draw a sketch , and find the probability of the reading The given values in Celsius degrees) ...
Friday, November 22, 2013 at 2:09pm

Statistics
Right
Friday, November 22, 2013 at 12:30pm

Statistics
Z = (mean1 - mean2)/standard error (SE) of difference between means SEdiff = √(SEmean1^2 + SEmean2^2) SEm = SD/√n If only one SD is provided, you can use just that to determine SEdiff. Find table in the back of your statistics text labeled something like "...
Friday, November 22, 2013 at 12:29pm

statistics (?)
Where is your data?
Friday, November 22, 2013 at 12:21pm

statistics
Is there a significant difference between first year post college incomes of graduates from public versus private institutions? Provide the IV, DV, and best method of analysi
Thursday, November 21, 2013 at 9:41pm

Statistics
Many dairy cows now receive injections of BST, a hormone intended to spur greater milk production. A group of 53 Jersey cows increased average milk production from 43 to 52 pounds per day, with a standard deviation of 4.8 lbs. Is this evidence that the hormone maybe effective ...
Thursday, November 21, 2013 at 7:31pm

Statistics
If the cases selected for one sample have no influence upon the cases selected for a second sample, then the samples are said to be: A) independent B) inconsistent C) dependent D) consistent A
Thursday, November 21, 2013 at 7:27pm

Statistics
The effectiveness of a headache medicine is tested by measuring the intensity of a headache in patients before and after drug treatment. The data consist of before and after intensities for each patient. Identify the design of the study. A) Paired t-test B) Two-sample t-test C...
Thursday, November 21, 2013 at 6:40pm

Statistics
A researcher wished to test the effect of the addition of extra calcium to yogurt on the "tastiness" of yogurt. Two different yogurts, one with extra calcium and one without the added calcium, were created from the same batch of yogurt. A group of 84 adult volunteers...
Thursday, November 21, 2013 at 6:39pm

statistics 201
You can use a one-sample z-test. z = (sample mean - population mean)/(standard deviation divided by the square root of the sample size) With your data: z = (375 - 350)/(150/√100) = 25/15 = 1.67 (rounded) If you use a 5% significant level for a one-tailed test (Ha: µ...
Thursday, November 21, 2013 at 4:50pm

statistics 201
A firm hires a pool of financial consultants to discuss portfolio recommendations with its clients. The CEO believes that another financial consultant should be hired if the average phone consultation exceeds 350 seconds. A random sample of 100 phone calls revealed a mean of ...
Thursday, November 21, 2013 at 2:48pm

statistics
„« If the city spends $145,000 on promotional expenditures. What will be the projected attendance at 95% confidence level?
Thursday, November 21, 2013 at 1:22pm

Statistics
% = mean ± ? SEm Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion/probability ([1-%]/2) and its Z score. Enter Z score for ?. Solve for intervals.
Thursday, November 21, 2013 at 11:30am

Statistics
A null hypothesis expects no difference.
Thursday, November 21, 2013 at 11:26am

Statistics
% = mean ± ? SEm SEm = SD/√n Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion/probability ([1-%]/2) to find the Z score. Insert that into ? position. Example: 95% = 74.8 &...
Thursday, November 21, 2013 at 11:24am

Statistics
The standard deviation for a population is σ = 15.3. A sample of 36 observations selected from this population gave a mean equal to 74.8. a) Make a 90% confidence interval for μ b) Construct a 95% confidence interval for μ. c) Determine a 99% confidence interval...
Thursday, November 21, 2013 at 11:11am

Statistics
Given the following null hypothesis, give an example of a Type II error. Ho: There is no difference in the level of understanding of this chapter between students who have previously taken a statistics course and students who have not previously takn a stastics course.
Thursday, November 21, 2013 at 9:55am

Statistics
given the following null hypothesis, give an example of a type I error. Ho: There is no difference between the number of males or females who go to their primary care physician for an annual exam.
Thursday, November 21, 2013 at 9:53am

Statistics
given the following information, determine the 68.3 percent, 95.5 percent, and 99.7 percent confidence intervals. Mean = 4.33, standard error of the mean =3
Thursday, November 21, 2013 at 9:46am

Statistics
Create a null hypothesis for the following research questions: a. What are the differences between emergency room shifts on medication errors? b. On a clinical trial of a new drug, what will be the effects over a currently used drug?
Thursday, November 21, 2013 at 9:41am

statistics
105.88
Thursday, November 21, 2013 at 6:51am

statistics
99% confidence interval z = 2.575 p hat = 68/87 =0.7816 E= Za/2 *sqrt((phat(1-phat)/n)) E = 2.575*sqrt(0.7816*0.2184/87) E = 0.1141 phat-E < P < Phat+ E 0.7816-0.1141 <p< .7816+.1141 0.6675 < p < 0.8957
Wednesday, November 20, 2013 at 10:02pm

statistics
conduct a study on support of ban on smartphones in class. 68/87 said yes. How large of a sample is needed to be sure the margin of error +/- 3.5% with 99% confidence. I know this is estimation...but I am not sure how to go about solving this problem.
Wednesday, November 20, 2013 at 9:38pm

statistics
I am conducting a study on support of ban on smartphones in class. 68/87 said yes to the ban. How large of a sample is needed to be sure the margin of error +/- 3.5% with 99% confidence. I know this is estimation...but I am not sure how to go about solving this problem.
Wednesday, November 20, 2013 at 9:19pm

Pages: <<Prev | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | Next>>

Post a New Question | Current Questions

Homework Help: Math

Search
Members