A sample of n=21 observations is drawn from a normal population with μ=990 and σ=220. Find each of the following:
A. P(x¯>1095)=
B. P(x¯<903)=
C. P(x¯>975)=
Given a normal population whose mean is 430 and whose standard deviation is 57, find each of the following:
A. The probability that a random sample of 3 has a mean between 439 and 449.
Probability =
B. The probability that a random sample of 14 has a mean between 439 and 449.
Probability =
C. The probability that a random sample of 24 has a mean between 439 and 449.
Probability =
The manufacturer of cans of salmon that are supposed to have a net weight of 6 ounces tells you that the net weight is actually a normal random variable with a mean of 6.07 ounces and a standard deviation of 0.18 ounce. Suppose that you draw a random sample of 29 cans. Find the probability that the mean weight of the sample is less than 6.03 ounces.
Probability =
Suppose that the number of customers who enter a supermarket each hour is normally distributed with a mean of 630 and a standard deviation of 160. The supermarket is open 16 hours per day. What is the probability that the total number of customers who enter the supermarket in one day is greater than 9300? (Hint: Calculate the average hourly number of customers necessary to exceed 9300 in one 16-hour day.)
Probability =
An accounting professor claims that no more than one quarter of undergraduate business students will major in accounting. What is the probability that in a random sample of 710 undergraduate business students, 186 or more will major in accounting?
Probability =
The proportion of eligible voters in the next election who will vote for the incumbent is assumed to be 54%. What is the probability that in a random sample of 530 voters, less than 48.5% say they will vote for the incumbent?
Probability =
A manufacturer of aspirin claims that the proportion of headache sufferers who get relief with just two aspirins is 63.7%. What is the probability that in a random sample of 410 headache sufferers, less than 59.9% obtain relief?
Probability =
A psychologist believes that 77% of male drivers when lost continue to drive, hoping to find the location they seek rather than ask directions. To examine this belief, he took a random sample of 50 male drivers and asked each what they did when lost. If the belief is true, determine the probability that less than 71% said they continue driving.
Probability =