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April 18, 2014

Homework Help: Math: Statistics

Recent Homework Questions About Statistics

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Statistics
3. The formula for finding sample standard deviation is ________________. a.𝑠=∑1▒𝑥W​22;𝑥 ̅^2 b.𝜎^2=(∑1▒(𝑋​−𝜇)^2 )/𝑁 c.𝑠^2=(∑1▒(𝑋​&#...
Friday, December 20, 2013 at 7:14pm

statistics
A student union wants to obtain a 90% confidence interval for the proportion of “full time” students who hold a part-time job for 20 hours or more per week. For this purpose, they want to interview a sample of full-time students. They want a margin of error to be at ...
Friday, December 20, 2013 at 12:33pm

Statistics
http://www.investopedia.com/terms/t/type​-ii-error.asp
Friday, December 20, 2013 at 11:51am

Statistics
http://www.investopedia.com/terms/t/type​-ii-error.asp
Friday, December 20, 2013 at 11:50am

Statistics
By definition, a Type I error is ____. a. rejecting a false H1 b. rejecting a false H0 c. rejecting a true H0 d. rejecting a true H1
Friday, December 20, 2013 at 8:35am

Statistics
Which of the following is an accurate definition of a Type II error? a. rejecting a false null hypothesis b. rejecting a true null hypothesis c. failing to reject a false null hypothesis d. failing to reject a true null hypothesis
Friday, December 20, 2013 at 8:33am

Statistics
What is the consequence of a Type II error? a. concluding that a treatment has an effect when it really does b. concluding that a treatment has no effect when it really has no effect c. concluding that a treatment has no effect when it really does d. concluding that a ...
Friday, December 20, 2013 at 8:32am

MATH Statistics
A student union wants to obtain a 90% confidence interval for the proportion of “full time” students who hold a part-time job for 20 hours or more per week. For this purpose, they want to interview a sample of full-time students. They want a margin of error to be at ...
Friday, December 20, 2013 at 1:07am

statistics
Margin of error : 0.372 95 % confidence interval. (15.228, 15.972)
Thursday, December 19, 2013 at 9:01pm

statistics
For these 90 times the mean was 15.60 minutes and the standard deviation s=1.80 minutes. Find the margin of error (round to 2 decimal places) and the 95% confidence interval for Julia’s average running time.
Thursday, December 19, 2013 at 8:54pm

Statistics
Choose d. None of the other choices are correct. Choice a: should read change alpha from .01 to .05. Choice b: should read change from a two-tailed test to a one-tailed test. Choice c: should read change sample size n = 25 to n = 100.
Thursday, December 19, 2013 at 5:33pm

Statistics
Thank you for you held once again your awesome.
Thursday, December 19, 2013 at 4:57pm

Statistics
When is there a risk of a Type II error? a. whenever H0 is rejected b. whenever H1 is rejected c. whenever the decision is "fail to reject H0" d. The risk of a Type II error is independent of the decision from a hypothesis test.
Thursday, December 19, 2013 at 4:01pm

Statistics
Which of the following will increase the power of a statistical test? a. Change Ą from .05 to .01. b. Change from a one-tailed test to a two-tailed test. c. Change the sample size from n = 100 to n = 25. d. None of the other options will increase power.
Thursday, December 19, 2013 at 4:01pm

statistics
Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion/probability (.25) and its Z score. Insert Z and other data into equation below and calculate. Z = (score-mean)/SD
Thursday, December 19, 2013 at 1:27pm

probability & statistics
m = (12-5)/(11-(-9) m =7/20 y = mx + b 5 = -9(7/20) +b 5 = -63/20 + b 163/20 = b y-intercept (0,163/20)
Wednesday, December 18, 2013 at 5:57pm

statistics
Solve the problem. Round to the nearest tenth unless indicated otherwise. The amount of rainfall in January in a certain city is normally distributed with a mean of 4.3 inches and a standard deviation of 0.3 inches. Find the value of the quartile .
Wednesday, December 18, 2013 at 5:44pm

probability & statistics
Find the slope and the y-intercept for the line that passes through (-9,5) (11,12)
Wednesday, December 18, 2013 at 4:33pm

Statistics
A national opinion poll found that 44% of all American adults agree that parents should be given vouchers good for education at any public or private school of their choice. Suppose that in fact the population proportion who feel this way is p=0.44. A) Many opinion polls have ...
Tuesday, December 17, 2013 at 7:24pm

Statistics
How would you check the Z table for the first problem?
Tuesday, December 17, 2013 at 7:09pm

Statistics 3
See your latest post.
Tuesday, December 17, 2013 at 7:08pm

Statistics 4
See your later post.
Tuesday, December 17, 2013 at 7:07pm

statistics 4.
See your later post.
Tuesday, December 17, 2013 at 7:00pm

statistics 3.
See your later post.
Tuesday, December 17, 2013 at 7:00pm

statistics 4.
Here are a few ideas to get you started. First problem: Try a one-sample z-test. Formula: z = (sample mean - population mean)/(standard deviation divided by the square root of sample size) Your data: sample mean = 2.6 population mean = 2.5 standard deviation = 0.5 sample size...
Tuesday, December 17, 2013 at 6:42pm

statistics 3.
Here are a few ideas to get you started. First problem: Use a formula to find sample size. Here is one for proportions: n = [(z-value)^2 * p * q]/E^2 ... where n = sample size, z-value is 1.645 (90% confidence interval), p = .5 (when no value is stated), q = 1 - p, ^2 means ...
Tuesday, December 17, 2013 at 6:26pm

statistics 3.
A student union wants to obtain a 90% confidence interval for the proportion of “full time” students who hold a part-time job for 20 hours or more per week. For this purpose, they want to interview a sample of full-time students. They want a margin of error to be at ...
Tuesday, December 17, 2013 at 5:23pm

statistics 4.
The manufacturer of Porshe 918 Spyder car claims that their car can go from 0 mph to 60 mph speed in less than 2.5 seconds. To test this claim, a sample of 40 new cars of this type were driven and their average 0-60 mph time was 2.6 seconds with a standard deviation of 0.5 ...
Tuesday, December 17, 2013 at 5:23pm

statistics-PLEASE HELP quick
Please only post your questions once. Repeating posts will not get a quicker response. In addition, it wastes our time looking over reposts that have already been answered in another post. Thank you.
Tuesday, December 17, 2013 at 2:48pm

statistics
This is probably too late, but does "etc." include the mean and standard deviation?
Tuesday, December 17, 2013 at 2:47pm

statistics
a) Ho: mean heights = Ha: mean heights ≠ b) SEm = SD/√n c) Z = (score-mean)/SEm 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. d) Once you ...
Tuesday, December 17, 2013 at 2:39pm

statistics 3.
A student union wants to obtain a 90% confidence interval for the proportion of “full time” students who hold a part-time job for 20 hours or more per week. For this purpose, they want to interview a sample of full-time students. They want a margin of error to be at ...
Tuesday, December 17, 2013 at 2:20pm

statistics 4.
The manufacturer of Porshe 918 Spyder car claims that their car can go from 0 mph to 60 mph speed in less than 2.5 seconds. To test this claim, a sample of 40 new cars of this type were driven and their average 0-60 mph time was 2.6 seconds with a standard deviation of 0.5 ...
Tuesday, December 17, 2013 at 2:19pm

statistics
proportion = 112/250 = .448 z = (.448 - .47) / sqrt(.47*.53/250) = -0.70 p-value = .2420 Since the p-value is greater than .05, do not reject the null hypothesis. The claim is not supported.
Monday, December 16, 2013 at 11:17pm

statistics
Use a 1.15 level of significance to test a claim that a true proportion is less than 47% when n=250 and x-112
Monday, December 16, 2013 at 11:07pm

statistics-PLEASE HELP quick
A family has four children and we assume that births occur with equal frequency for both sexes. Construct a sample space for all possible family arrangements allowing for order of birth to count. a) How many different arrangements are possible? b)find P (three are boys)= c)...
Monday, December 16, 2013 at 11:05pm

statistics
Z = (score -mean) /sd z = (126.2-135)/4 z = -9.8/4 = -2.45 z-table
Monday, December 16, 2013 at 11:04pm

statistics
4. Are women getting taller? In one state, the average height of a woman aged 20 years or older is 63.7 inches in 1990. A random sample of 100 women is taken to test if women’s mean height today is different from 1990. The mean height of the 100 surveyed women is 63.9 ...
Monday, December 16, 2013 at 10:13pm

Statistics 4
The manufacturer of Porshe 918 Spyder car claims that their car can go from 0 mph to 60 mph speed in less than 2.5 seconds. To test this claim, a sample of 40 new cars of this type were driven and their average 0-60 mph time was 2.6 seconds with a standard deviation of 0.5 ...
Monday, December 16, 2013 at 9:42pm

statistics
The breaking strength (in pounds) of a certain new synthetic is normally distributed, with a mean of 135 and a variance of 16. The material is considered defective if the breaking strength is less than 126.2 pounds. What is the probability that a single, randomly selected ...
Monday, December 16, 2013 at 9:39pm

Statistics 3
A student union wants to obtain a 90% confidence interval for the proportion of “full time” students who hold a part-time job for 20 hours or more per week. For this purpose, they want to interview a sample of full-time students. They want a margin of error to be at ...
Monday, December 16, 2013 at 9:38pm

statistics
I have done an entire project based on football scores from a certain team over the last 3 years and I'm not sure what information I can get from my answers. Ive done a frequency distribution table, Ogive, Histogram,cumulative frequency table, frequency polygon, etc. and I...
Monday, December 16, 2013 at 7:54pm

statistics-PLEASE HELP quick
I understand most of the formulas however Im not sure what the answers tell me. I did a frequency distribution table for all points scored by a football team over 4 years, but I don't understand what my answers mean and I don't want to look stupid in front of my class...
Monday, December 16, 2013 at 7:47pm

Statistics
Note: For the second problem, we use the normal approximation to the binomial distribution when finding the mean and standard deviation.
Monday, December 16, 2013 at 6:48pm

Statistics
Use z-scores. First problem: z = (x - mean)/(sd/√n) Find two z-scores: z = (2.4 - 2.5)/(0.2/√50) = ? z = (2.8 - 2.5)/(0.2/√50) = ? Finish the calculations. Next, check a z-table to find the probability between the two scores. Find mean and standard deviation...
Monday, December 16, 2013 at 6:46pm

Statistics 2
Formulas: CI90 = mean ± 1.645 (sd/√n) CI95 = mean ± 1.96 (sd/√n) For the first part, substitute the mean, standard deviation, and sample size into the appropriate formulas to determine the confidence intervals. This will help you answer the questions ...
Monday, December 16, 2013 at 6:32pm

statistics in psychology
Using an online calculator, we have 4 data pairs (x,y): (1,10) (1,8) (2,4) (4,-2) Regression equation: y = a + bx y = 12.3 - 3.67x This is the line of best fit. You can plot the scatter graph using the points above (x,y) to see how close the points are to the regression line...
Monday, December 16, 2013 at 6:23pm

statistics in psychology
12. Four research participants take a test of manual dexterity (high scores mean better dexterity) and an anxiety test (high scores mean more anxiety). The scores are as follows. Person Dexterity Anxiety 1 1 10 2 1 8 3 2 4 4 4 –2 (a) Scatter Graph: Scatter and Regression
Monday, December 16, 2013 at 3:40pm

Statistics 2
The body temperature of healthy human beings can be assumed to have a normal distribution with mean  and standard deviation . Body temperature measurements taken from a sample of 130 healthy individuals shows the sample mean temperature to be 98.249O F and ...
Monday, December 16, 2013 at 1:21pm

Statistics
A manufacturing facility produces iron rods whose mean diameter is 2.5 inches with a standard deviation of 0.2 inch. If a sample of 50 metal rods produced by the facility were randomly selected, what is the probability that the mean of these rods will lie between 2.4 inches ...
Monday, December 16, 2013 at 12:53pm

Statistics
I will start it for you. Most numbers can be obtained in more than one way. 2 and 12, the only no pay numbers, can only be obtained one way. 3 = 2,1 or 1,2 = 2 ways 4 = 2,2 or 3,1 or 1,3 = 3 ways 5 = 3,2 or 2,3 or 1,4 or 4,1 = 4 ways etc.
Monday, December 16, 2013 at 12:31pm

statistics
No, unless you have more data that was not posted.
Monday, December 16, 2013 at 12:03pm

Statistics
You are so welcome
Sunday, December 15, 2013 at 6:21pm

Statistics
thank you!
Sunday, December 15, 2013 at 6:19pm

Statistics
Yes
Sunday, December 15, 2013 at 6:18pm

Statistics
so would it be true?
Sunday, December 15, 2013 at 6:15pm

Statistics
The null hypothesis will be that all population means are equal, the alternative hypothesis is that at least one mean is different.
Sunday, December 15, 2013 at 6:10pm

Statistics
True or False: For ANOVA you will reject the null hypothesis is the variability within a sample is greater than the variability among samples?
Sunday, December 15, 2013 at 6:02pm

statistics
3. Assuming α = 0.05 and that the population is normally distributed, is there enough evidence to support a claim that the mean amount of servings teenage females drink is less than or equal to 1.5 servings per day?
Saturday, December 14, 2013 at 7:57pm

Statistics
In a game you roll two fair dice. If the sum of the two numbers obtained is 3,4,9,10 or 11 you win $20. If the sum is 5,6,7 or 8 you pay $20. However if the scores on the dice are the same no one is required to pay. (a) Construct a probability distribution table for the event...
Saturday, December 14, 2013 at 4:30pm

Statistics
I assume this is for a distribution of means. Z = (score-mean)/SEm SEm = SD/√n Plug in data and solve for Z.
Saturday, December 14, 2013 at 12:11pm

statistic
Sometimes we can answer specific questions if a math or engineering or economics or science teacher is around who does statistics.
Friday, December 13, 2013 at 9:44pm

statistics
9. Explain the transformation needed to convert the following data to a linear data set. {(1, 0.98), (2, 1.39), (3, 1.71), (4, 1.98), (5, 2.22), (6, 2.43)} (6 points)
Friday, December 13, 2013 at 7:15pm

Statistics
For a population with a mean of µ=60 and standard deviation of Ợ=24, find the z=score corresponding to each of the following samples a. M=63 for sample of n=16 scores b. M=63 for sample of n=36 scores c. M=63 for sample of n=64 scores
Friday, December 13, 2013 at 7:12pm

Statistics
is this statement true or false.
Friday, December 13, 2013 at 6:42pm

statistics
Variance =38.2
Friday, December 13, 2013 at 6:26pm

statistics
what is the variance of 18, 16, 12, 2, 11
Friday, December 13, 2013 at 6:12pm

Statistics (?)
What is your question?
Friday, December 13, 2013 at 1:29pm

Statistics
SEm = SD/√n From this equation, you can see why it is false.
Friday, December 13, 2013 at 1:29pm

Statistics
Standard deviation (SD) = square root of variance 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 (.05) related to the Z score. Insert the values into ...
Friday, December 13, 2013 at 12:44pm

Stats
Z = (score-mean)/SEm SEm = SD/√n Assuming a normal distribution, find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion/probability (.05) and its Z score. Insert Z score and other data into...
Friday, December 13, 2013 at 12:29pm

Statistics
Thank you for all your help.
Friday, December 13, 2013 at 10:22am

Statistics
86.2? :D
Friday, December 13, 2013 at 4:06am

Statistics
Scores on a certain exam are normally distributed with a mean of 78 and a variance of 25. What is the score obtained by the top 5% of the students? I do not understand the 5% part. What does the tail look like on the bell-shaped graph?
Friday, December 13, 2013 at 4:03am

Statistics
n1-25, n2-36, s1 power 2=50, s2 2 power=72, m1=100. m2=105
Thursday, December 12, 2013 at 11:35pm

Statistics
As sample size increases, the value of the standard error also increases. Ans false
Thursday, December 12, 2013 at 10:28pm

mah statistics
Mean = 0(.5) + 1(.12) + 2( .23) + 3(.3) + 46.16) + 5(.1) +5 (.04) = ? variance = 0^2(.5) + 1^2(.12) + 2^2 (.23) + 3^2(.3) + 4^2(.16) +5^2 (.1) + 5^2(.04) = ? Standard deviation = sqrt(variance -mean ^2))
Thursday, December 12, 2013 at 10:21pm

Statistics
True or False The mean for a sample of n = 4 scores has a standard error of 5 points. This sample was selected from a population with a standard deviation of ċ = 20.
Thursday, December 12, 2013 at 10:19pm

Statistics
True or False As sample size increases, the value of the standard error also increases.
Thursday, December 12, 2013 at 10:18pm

mah statistics
the following table gives the number of camcorders sold on a given day in an electronics store X: 0, 1, 2, 3, 4, 5, 5, P(x) 0.5, .12, .23, .3, .16, .1, .04 find the mean, variance, and standard deviation of the daily sales of camcorders in the store.
Thursday, December 12, 2013 at 6:52pm

Statistics
The sample size reduces variability of distribution of means as it gets larger, but does not effect the expected value for the sample mean.
Thursday, December 12, 2013 at 3:16pm

Statistics
Using P ≤ .05, if the probability the results would occur by chance is P > .05, you would accept the null hypothesis. By using any level of significance, if it equals or is less than that level, you would be assuming that the results indicate significant differences. ...
Thursday, December 12, 2013 at 3:11pm

Statistics
a) Use ratio and proportion... 500 tagged birds/n total birds = 20/215 by cross products: 20n = 500 * 215 20n = 107,500 n = 107,500 / 20 = 5,375 b) ? c) In early spring the recently hatched baby birds are probably not available for capture, as they are still in the nest. ...
Thursday, December 12, 2013 at 2:35pm

Statistics
How is the rejection region defined and how is that related to the z-score and the p value? When do you reject or fail to reject the null hypothesis? Why do you think statisticians are asked to complete hypothesis testing? Can you think of examples in courts, in medicine, or ...
Thursday, December 12, 2013 at 12:16am

Statistics
Can someone help me do this problem? A group of environmentalist are trying to estimate the population of the state rid in clear view park. They capture a sample of 500 birds in early spring and tag them. in august they capture 215 birds, of which 20 are tagged. a) use the ...
Thursday, December 12, 2013 at 12:12am

Statistics
True or False According to the central limit theorem, the expected value for a sample mean becomes smaller, approaching zero, as the sample size approaches infinity.
Wednesday, December 11, 2013 at 9:39pm

Statistics
True or False In order for the distribution of sample means to be normal, it must be based on samples of at least n = 30 scores.
Wednesday, December 11, 2013 at 9:39pm

Statistics
Thank you for the help.
Wednesday, December 11, 2013 at 9:36pm

statistics
Victor or Junior, did you multiply my response to find the answer?
Tuesday, December 10, 2013 at 4:25pm

Statistics
Formula: z = (x - mean)/(sd/√n) With your data: z = (76 - 70)/(18/√9) = 6/6 = 1 Choice: c
Tuesday, December 10, 2013 at 3:49pm

Statistics
False. Should read "...the sampling distribution of the mean will be equal to the population mean." (Central Limit Theorem)
Tuesday, December 10, 2013 at 3:45pm

STATISTICS
How about a? Check this.
Tuesday, December 10, 2013 at 2:59pm

Math :)
first, check the differences: 8.6 2.0 1.6 2.8 1.3 Doesn't look good, since there's no obvious slope. Is this a class in statistics, where you cover linear regression? The 62.5 looks like an outlier.
Tuesday, December 10, 2013 at 12:10pm

Statistics
well, 3/4 of the scores were below 69. That leaves 1/4 above. What's 1/4 of 135?
Tuesday, December 10, 2013 at 11:54am

Statistics
Multiple choice question that's hard to figure out and understand.(information provided) Ten members of a fraternity take a statistics course. Here are their scores on the first exam in the course: 61,74,47,60,62,63,65,79,55,85. The question states: In all, 135 students ...
Tuesday, December 10, 2013 at 11:52am

statistics
Multiple choice question that's hard to figure out and understand.(information provided) Ten members of a fraternity take a statistics course. Here are their scores on the first exam in the course: 61,74,47,60,62,63,65,79,55,85. The question states: In all, 135 students ...
Tuesday, December 10, 2013 at 11:51am

statistics
You have a lot of unnecessary data given to answer your question. .25 * 135 = ?
Tuesday, December 10, 2013 at 10:03am

Statistics
disjoint
Monday, December 9, 2013 at 10:05pm

Business Math and Statistics
Ill be concise:60% of people in survey had income greater than 25k, 40% under 25k. Further, same survey, 70% have exactly 2 cars, while 30% have a different number than 2. The probability that the residents own 2 cars IF income is over 25k is 80%. what is the probability of a ...
Monday, December 9, 2013 at 9:46pm

statistics
Ten members of a fraternity take a statistics course. Here are their scores on the first exam in the course. 61,74,47,60,62,63,65,79,55,85. In all 135 students took the exam. The third quartile for all 135 scores was 69. How many students had scores higher than 69?
Monday, December 9, 2013 at 9:17pm

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