Recent content by ChrisBlack

Homework Statement Janet sells cookware at home parties, she wants to estimate the average amount a client spends at each party. A random sample of 35 receipts gave a mean of X bar = $34.70 with standard deviation s = %4.85. a) find a 90% confidence interval for the average amount spent by...

Sorry for the late reply. Yes, i can see how that is the same problem and i have worked with the distribution of coin tosses. So far all I have really done is identify the variables, N (number of students, 45) P (.68), q (.32) standard deviation (.047), and mean (.68). I have to sleep so I will...

So no more than 30 students can favor it. This does not sound like anything I have done in class so far, does it have to do anything with the fact that 68% of the data falls within 2 standard deviations of the mean?

Homework Statement 68% of students favor a new policy, we are interested in the proportion of 45 students in a math class who favor the same policy. What is the probability that the proportion of the class that favors the policy is no more than two-thirds? Homework Equations The...

The equation I posted at the top is the correct one to change the Z value to an X right? the answer i got it 29.91, or 30 minutes

The problem says that the shop does not want to give more than 1% of customers a free oil change, so I would think it would be over the mean, which makes sense if the Z score is positive, but i don't see why it's positive. Sorry, I should have written the whole problem

Homework Statement The mean is 17.8 and the standard deviation is 5.2. The shop does not want to give more than 1% of its customers free service, how long should the guarantee be? (cut the problem short, the rest was just story) Homework Equations I think the equation I would use is X =...

Thanks! I just thought that 48/289 seemed too small to be the answer, but I guess it is what it is.

So (a) would be 48/289 then, correct? and for (b) it would be 48/272, reduced to 3/17? Thanks, I thought they would be mutually exclusive because both events can not happen at the same time, since only 1 ball is chosen at a time

Homework Statement An urn contains 17 balls identical in every respect except color. There are 6 red balls, 8 green balls, and 3 blue balls. A) you draw 2 balls from the urn but replace the first ball before drawing the second. find the probability that the first ball is red and the second...