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a population consists of two strata, H and L of sizes 100,000 and 500,000 and standard deviations 20 and 12 respectively. a stratified sample of size 100 is to be taken.
What was the minimum exam score required for a B in Statistics? What was the minimum exam score required for a B in Psychology?
If a Boeing 767-300 is full of 213 adult male passengers and each is assumed to have 20 pounds of carry-on baggage, find the probability that the mean passenger weight is greater than 195. Does the
A carpal tunnel syndrome is a common wrist complaint resulting from a compressed nerve. Perform a two-tailed test comparing the response rates (proportions) at α=0.05.
Compare the expression obtained in part b to the variance of usual estimate , which is the product of N and the average audited value. Under what circumstances would the proposed method be more accu
a circuit has 8 switches, two are defective, if you select 2 switches at random and test them, find the probability thatt the second one is defective given that the first one is defective.
In a shipment of 57 vials, only 17 do not have hairline cracks. If you randomly select one vial from the shipment, what is the probability that it has a hairline crack?
a random sample of 121 checking accounts at bank showed an average daily balance of $280 the standard deviation of the population is known to be $6
Using the .05 level, do the results support the researcher's theory? (a) Use the steps of hypothesis testing, (b) sketch the distributions involved.
The daily closing stock price of Alcoa (Aluminum Corporation of America) follows a normal distribution with a mean of $46:50 and a standard deviation of $22.20. We select a day at random. Find the p
John Davis, a manager of a supermarket, wants to estimate the proportion of customers that will be using food stamps at his store. How large a sample is required to estimate the true proportion to w
In order to estimate the average electric usage per month, a sample of 196 houses was selected, and the electric usage determined.
We have a box of 12 light bulbs. The probability that a particular light bulbs lights on opening is 0.95. This meets the binomial assumptions.
A nurse researcher found that the mean values of two groups on anxiety were different from each other with a p-value of 0.35 (alpha - 0.05). A nurse reading this finding knows that the researcher sh
If in a random poll of 250 residents, 150 residents were in favor, how accurate is this result as an estimate of the proportion?
Is it possible that exactly half of all senior executives believe that the most common job interview mistake is to have little or no knowledge of the company. Why or Why not?
Hourly wages in a particular industry are normally distributed with a mean of $13.20 and a standard deviation of $2.50. A random sample of 40 workers was taken from a certain fi rm in this industry
A recent study by the Island Resort Taxi Drivers Association showed that the mean fare charged for service from the beach to the airport is $18.00 and the standard deviation is $3.50. We select a s
In Tech City, 90 percent of the households have satellite TV. 10 Tech City households are picked at random. We can think of this as a binomial experiment.
A consumer watchdog agency selects a random sample of 40 taxpayers and finds the standard deviation of the time to prepare, copy and mail their tax return is 80 minutes. a. What is the standard erro
Is the true proportion of college women that have been on a diet within the last 12 months in this survey more than the stated proportion?
We have obtained the ages and amounts for treats at the movies. We let the x variable be age and the y variable be the amount data. Here are the summary data:
Assuming that the standard deviation of the population of completion times is 10.4 minutes, what is the minimum sample size needed for the managers to be 95% confident that their estimate is within
The following frequency table shows the number of customers per day at a small restaurant.Number of Customers Number of Days
Assume that the lives of all such bulb (approximately) normally distribution. Make the 99% confidence intervals for the variance and standard deviation of the lives of all such bulbs.