A study at a college in the west coast reveals that, historically, 45% of their students are minority students. If random samples of size 75 are selected, 80% of the samples will have less than ________% of minority students.
Answer Key: 49.83
Assume that house prices in a neighborhood are normally distributed with standard deviation $20,000. A random sample of 16 observations is taken. What is the probability that the sample mean differs from the population mean by more than $5,000? For calculations, use your book table E.2.
Answer Key: 0.4532
I need to know how do to solve these. The answers have been given but i need to know how they got those asnwers.
For the first problem I think i need to figure the standard dev
I know for the second problem i need to use a z score but i dont know how to figure out the sample and population mean from the info given.
Try this:
.845 = (x - 75*.45)/sqrt(75*.45*.55)
Once you solve for x you need to divide by the sample size of 75 to put it in % of minority students as the problem asks. The .845 on the left hand side of the equation comes from standard normal distribution corresponding to 80%.
.845 = (x - 75*.45)/sqrt(75*.45*.55)
ok so .845^2 = (x - 75*.45)/(75*.45*.55)
(.845^2)*(75*.45*.55)=(x - 75*.45)
so (.845^2)*(75*.45*.55) + (75*.45) = X << is this correct because i come with some weird number like 45.00 or something....darn im still stumped