6. A large population of overdue bills has balances that follow a normal curve. When we take a sample of 100 of these the average is $500 and the SD is $100.
(a) What statement can you make about the range$300 to $700?
(b) What statement can you make about the range $480 to $520?
10. Pollsters try to determine whether or not a person is a ‘likely voter’ before they count their opinion in a poll. If we assume 40% of the registered voters will actually vote, in a random sampleof 100 registered voters we can be 95% confident that somewhere between ________ and ________ of them will actually vote. Fill in the blanks with a number.
Please show your work so I can see what you did and help me better understand.
a) Based on the Rule of Thumb (alternatively known as the 68-95-99.7 rule), we know that 95% of the values lie between +/- 2 standard deviations of the mean for a normal distribution. Since our standard deviation is $100 and our mean is $500, +/- 2 standard deviations translates to the exact range we are asked about. We can thus say that on average, we would expect 95 …
The solution is 261 words of explained calculations on how to answer these normal curve and range questions.