Q1. A sample of 144 cans of coffee showed an average weight of 16 ounces. The st
ID: 3066778 • Letter: Q
Question
Q1. A sample of 144 cans of coffee showed an average weight of 16 ounces. The standard deviation of the population is known to be 1.44 ounces. Construct a 68.26% confidence interval for the mean of the population. Use exactly two decimal places for your answers.
Q2. A sample of 144 cans of coffee showed an average weight of 16 ounces. The standard deviation of the population is known to be 1.44 ounces. Construct a 95.44% confidence interval for the mean of the population. Use exactly two decimal places for your answers.
Q3. A random sample of 81 credit sales in a department store showed an average sale of $68.00. From past data, it is known that the standard deviation of the population is $27.00. Construct a 95% confidence interval of the population mean. Use exactly two decimal places for your answers.
Q4. Annual income of pilots is normally distributed. A random sample of 25 airline pilots showed an average yearly income of $99,000 with a standard deviation of $20,000. Build a 95% confidence interval for the average yearly income of all pilots. No decimal place is required in
Q5. Monthly cable bill is normally distributed. The average monthly cable bill of a random sample of 16 residents of a city is $130 with a standard deviation of $40. Construct a 90% confidence interval for the mean monthly cable bills of all residents. Use exactly two decimal places for your answers.
Q6. The weight of people who go bungee jumping is normally distributed. A sample of 49 prospective bungee jumpers is taken before the jump. The average weight from the sample was 155 pounds with a standard deviation of 35 pounds. Construct a 99% confidence interval for the average weight of the population of bungee jumpers. Use exactly two decimal places for your answers.
Q7. A researcher is interested in determining the average number of years employees of a company stay with the company. If past information shows a standard deviation of 7 months, what size sample should be taken so that at 95% confidence the margin of error will be 3 months or less? Your answer should be an integer (a while number without any decimals).
Q8. In a sample of 400 individuals, 200 indicated they are Democrats. Develop a 95% confidence interval for the proportion of people in the population who are Democrats. Use exactly three decimal places for your answers.
Q9. In a blind test of 150 consumers chosen at random, 60 indicated their preference for freshly baked bread over pre-packaged bread. Determine a 95% confidence interval for the proportion of consumers who will show preference for freshly baked bread in a blind test. Use exactly four decimal places for your answers.
Explanation / Answer
#1.
#2.
#3.
#4. here t distribution is used as n < 30
CI for 68.26% n 144 mean 16 z-value of 68.26% CI 0.9998 std. dev. 1.44 SE = std.dev./sqrt(n) 0.12000 ME = z*SE 0.11998 Lower Limit = Mean - ME 15.88002 Upper Limit = Mean + ME 16.11998 68.26% CI (15.88 , 16.12 )Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.