1. Suppose a population has a mean weight of 180 pounds and a standard deviation of 25 pounds. A sample of100 items is drawn from this population. What is the standard error of the mean?
2. The amount of corn chips dispensed into a 16-ounce bag by the dispensing machine has been identified aspossessing a normal distribution with a mean of 16.5 ounces and a standard deviation of 0.2 ounce. Suppose100 bags of chips were randomly selected from this dispensing machine. Find the probability that the samplemean weight of these 100 bags exceeded 16.6 ounces.
3. One year, professional sports players' salaries averaged $1.9 million with a standard deviation of $0.7 million.Suppose a sample of 100 major league players was taken. Find the approximate probability that the averagesalary of the 100 players exceeded $1.1 million.
4. Furnace repair bills are normally distributed with a mean of 267 dollars and a standard deviation of 20 dollars.If 64 of these repair bills are randomly selected, find the probability that they have a mean cost between 267dollars and 269 dollars.
5. The owner of a computer repair shop has determined that their daily revenue has mean $7200 and standarddeviation $1200. The daily revenue totals for the next 30 days will be monitored. What is the probability thatthe mean daily revenue for the next 30 days will exceed $7500?
6. A national caterer determined that 87% of the people who sampled their food said that it was delicious. Arandom sample of 144 people is obtained from a population of 5000. The 144 people are asked to sample thecaterer's food. If p ^ is the sample proportion saying that the food is delicious, what is the mean of the samplingdistribution of p ^ ?
7. Find the critical t-value that corresponds to 99% confidence and n = 10.
8. Find the critical t-value that corresponds to 90% confidence and n = 15.
9. A computer package was used to generate the following printout for estimating the sale price of condominiumsin a particular neighborhood.
X = sale_price
SAMPLE MEAN OF X = 46,600
SAMPLE STANDARD DEV = 13,747
SAMPLE SIZE OF X = 15
CONFIDENCE = 90
UPPER LIMIT = 52,850.60
SAMPLE MEAN OF X = 46,600
LOWER LIMIT = 40,349.40
A friend suggests that the mean sale price of homes in this neighborhood is $43,000. Comment on your friend's suggestion.
A) Based on this printout, all you can say is that the mean sale price might be $43,000.
B) Your friend is wrong, and you are 90% certain.
C) Your friend is correct, and you are 90% certain.
D) Your friend is correct, and you are 100% certain.
10. A simple random sample of size n < 30 has been obtained. From the boxplot, judge whether a t -interval should be constructed.
A) Yes; the data appear normally distributed and there are no outliers
B) No, there are outliers and the data are not normally distributed
C) No, there are no outliers but the data are not normally distributed
D) No; the data appear roughly normally distributed but there are outliers
11. Construct a 95% confidence interval for the population mean, μ. Assume the population has a normal distribution. A sample of 20 part-time workers had mean annual earnings of $3120 with a standard deviation of $677. Round to the nearest dollar.
12. Construct a 98% confidence interval for the population mean, μ. Assume the population has a normal distribution. A study of 14 car owners showed that their average repair bill was $192 with a standard deviation of $8. Round to the nearest cent.
13. In a random sample of 60 dog owners enrolled in obedience training, it was determined that the mean amount of money spent per owner was $109.33 per class. Assuming the population standard deviation of the amount spent per owner is $12, construct and interpret a 95% confidence interval for the mean amount spent per owner for an obedience class.