How do I find the probability?

Question

The population mean is $51,400 and the population standard deviation is $4,000. When the sample size is n = 20, there is a 0.4246 probability of obtaining a sample mean within +/- $500 of the population mean.

a. What is the probability that the sample mean is within $500 of the population mean if a sample of size 40 is used

b. What is the probability that the sample mean is within $500 of the population mean if a sample of size 80 is used

Answer 1

To find the probablility, take the number of whatever you're comparing it to then put that number over the number in all (fraction form). Example: There are 10 girls in Ms. Burns's class and 13 boys. There are 23 students in all. To find the probability of girls to the number of students in all, put the number of girls (10) as the numerator in a fraction or ratio type, then put the number of students in all as the denominator (23). Answer:  10/23 or 10:23 or 10 to 23. But if you want an answer like:most likely, likely, unlikely, probably, just see if the number of girls is  (for example) half of the amount of students in all and if it is higher than half, it's mostly likely or likely and if it's less than half, it's less likely or unlikely and if it is about half,  it's probably.

#smart

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