will occur is different from the probabilities that a will occur and that B. will occur.
Refer to the following data to answer questions 7 and 8. Just the answer
A random sample of song playing times in seconds is as follows:
7. Find the standard deviation. 28.65
8. Are any of these playing times considered unusual in the sense of our textbook? Explain. Does this differ with your intuition? Explain. The longest playing time, 293 seconds, could be considered somewhat unusual in that it is more than 1.5 standard deviations away from the mean, meaning more than 93% of data in the population (if normally distributed) would fall below this level -- 93% of songs would be shorter. Intuition says that this is not the case, and that though the song is longer this is simply part of the variation that exists in music.
Refer to the following situation for Questions 9, 10, and 11.
The boxplots below show the real estate values of single family homes in two neighboring cities, in thousands of dollars.
For each question, give your answer as one of the following: (a) Tinytown; (b) BigBurg; (c) Both cities have the same value requested; (d) it is impossible to tell using only the given information. Please explain answer...
Which city has greater variability in real estate values? (b) BigBurg
10. Which city has the greater percentage of households with values $85,000 and over? (c) Both cities have the same value requested
11. Which city has a greater percentage of homes with real estate values between $55,000 and $85,000? (a) Tinytown
12. A random sample of the lifetime of 49 UltraIllum light bulbs has a mean of 3,960 hours and a standard deviation of 200 hours. Construct a 95% confidence interval estimate of the mean lifetime for all UltraIllum light bulbs.
Mean +/- z * (Standard Deviation/sqrt n)
3,960 +/- 1.96 * (200/sqrt 49) = 3,960 +/- 56 = 3904/4016
95% confidence interval population mean estimate is 3904 to 4016.
Refer to the following information for Questions 13 and 14.
There are 500 students in the senior class at a certain high school. The high school offers two Advanced Placement math / stat classes to seniors only: AP Calculus and AP Statistics. The roster of the Calculus class shows 95 people; the roster of the Statistics class shows 86 people. There are 43 overachieving seniors on both rosters.
13. What is the probability that a randomly selected senior
