According to Quantcast analytics of CrossFit.com, 59% of CrossFitters have children. Suppose we take a random sample of 40 Crossfitters and find the sample proportion (ˆp) that have children. We repeat this process many times. (a) What do you expect the mean of the ˆp’s to be? (b) What do you expect the standard deviation of the ˆp’s to be? (c) What do you expect the shape of the ˆp’s to be?

Nintendo is doing a classic game competition for the anniversary of Super Mario Bros. The average runtime for a straight playthrough is 1 hour and 58 minutes (with a standard deviation of 6 minutes). Out of all of the players who compete in this competition (120 players), the fastest 10% will get a chance at a special reward. What would be the benchmark playthrough time for this competition?

You may need to use the appropriate appendix table or technology to answer this question. A random sample of 121 checking accounts at a bank showed an average daily balance of $290. The standard deviation of the population is known to be $77. (a) Is it necessary to know anything about the shape of the distribution of the account balances in order to make an interval estimate of the mean of all the account balances? Explain. No, the sample is large and the standard deviation of the population is known so we do not need to know anything about the shape of the distribution. Yes, the mean is larger than the standard deviation so we also need to know that the shape of the distribution is at least approximately bell shaped. No, the standard deviation is larger than the mean so we do not need to know anything about the shape of the distribution. No, the mean is larger than the standard deviation so we do not need to know anything about the shape of the distribution. Yes, the sample is large…

The honors program at Brad's university only accepts students with an entrance exam score over 400. What percentage of students would be eligible if the students at Brad's school have an average exam score of 250, with a standard deviation of 80?

what are the corresponding standard deviation using each of these pairs? What would you infer from these derived scales/standard deviations?

IF your mean is 832 and your standard deviation is 86, what values like in the 36% range?? How do you figure it out??