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# Thread: anyone really good with probability and statistics???

1. ## anyone really good with probability and statistics???

if anyone here is good with prob/stat, i could greatly appreciate your help. i really need a B in this class and i have 2 tests and the final coming up in 2 weeks. i will be getting these tests from a friend who took the class previously. they wont be the tests exactly but, they will be the same format and stuff. so if anyone can help, i would appreciate it more than you could ever know. ill be getting these tests tomorrow, but i wanted to get out word as quick as i could.

2. give me an example of a problem bro

4. I had a semster with Quantitative Decision Making and another semester with Stats. Got an A in QDM and a B in Stats. Same course but I never went to my stats class since it was the same shit.

5. Sorry bro, can't help you out there- i just dropped my elementary statistics class cuz i never went and my grade was currently a D.

6. alright, i have my tests, any of you guys who wanted an example want me to just post the test?

7. Yeah just post up the whole test.

8. 1) The mean score on a peace corps application test is 80. A sample of 16 applicants took the test and had a sample mean of 86 and standard deviation of 14.3. Does the data provide sufficient evidence to conclude that the sample mean is different than 80 at the .05 level.

a) find the calculated value (nearest hundredth)
b) write the critical value for the test for an (alpha) of .05.
c) the sample mean (circle one) is or is not different.

2) A sporting goods manufacturer produces both white and yellow golf balls and claims that 76% of the balls sold are white. A marketing study showed that of 410 balls sold, 306 were white and the remaining yellow. Is there eveidence to support the manufacturers claim at the .05 level.

a) find the calculated value (nearest hundredth)
b) write the critical value for the test for an (alpha) of .05.
c) there is (circle one) is or is not significant support for the claim.

3) The EPA sets a limit of 5 parts per million of PCB in water. A manufacturing firm producing PCB discharges small amounts from a plant. Management plans to halt production if the mean amount of PCB in the effluent exceeds 3ppm. A random sample of 50 water specimens produced a mean of 3.6 with a standard deviation of 1.6. Do these statistics provide sufficent evidence to halt production at a .05 level?

a) find the calculated value (nearest hundredth)
b) write the critical value for the test for an (alpha) of .05.
c) there (circle one) is or is not enough evidence to halt production.

4) Recent experiments suggest it may be possible for a person to control blood pressure levels if the person is trained in biofeedback. One experiment resulted in this table showing values before and after biofeedback training. Does the data provide sufficient evidence show that blood pressure readings after biofeedback training are lower than before?

name: before: after:
bob 136 130
bill 201 180
sue 166 150
caren 150 153

a) find the calculated value
b) write the critical value for the test.
c) blood pressure (circle one) is or is not lower afterward.

5) A random sample contains 80 women. Half train with a running program and half train with a stair climbing program. After six weeks all the women are given a fitness test that provides a score between 0 and 100. The results are in the table. At the .01 level, is the mean value differnt than the mean value for stair climbing?

mean s squared
running 79.6 264
stair climbing 71.6 256

a) find the calculated value
b) write the critical value for the test for an (alpha) of .01
c) there (circle one) is or is not a difference in the means.

6) The atomic industrial forum randomly sampled 9 coal plants and 11 nuclear plants and reports that mean coal produced energy costs 3.6 cents per kilowatt-hour compared to 3.1 cents for nuclear power with variances of .16 and .04 respectively. Does this information provide sufficient evidence at the .01 level to say that cost of nuclear- generated power is lower on average than coal produced power?

a) find the calculated value
b) write the critical value for the test for an alpha of .01
c) nuclear power (circle one) is or is not

7) A compressed air apparatus may replace the needle in administering vaccines. The apparatus can be set to inject different amounts of the serum, but the variance in the amount injected to the person must not be greater than .06 to ensure proper inoculation. A random sample of 26 injections resulted in a variance of .106. Do the data provide sufficient evidence at the .01 level to indicate the apparatus is not working properly?

a) find the calculated value
b) write the critical value for the test for an alpha of .01.
c) the apparatus (circle one) is or is not working properly.

8) A manufacturer collects records on the amount of time before a repair of its two models of washing machines. The standard deviations of the times for the two washers based on samples of 6 each, are 2.6 and 6.6. Is the variance of the second significantly different than the variance of the first at the .01 level?

a)find the calculated value
b) write the critical value for teh test for an alpha of .01
c) there (circle one) is or is not a difference in the variances

9) In a random sample of 796 male passengers and 263 female managers, 86% of the male managers and 65% of the female managers were married. What is the pooled p value (nearest thousandth) used to determine if the data provide sufficient evidence to indicate the percentage of the married male managers is different than the percentage of female managers at the .01 level?

this is some tough stuff, so any help would be appreciated.

kenny

9. bump anyone?

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