The Department of Education would like to test the hypothesis that the average debt load of graduating students with a bachelor’s degree is equal to $17,000. A random sample of 34 students had an average debt load of $18,200. It is believed that the population standard deviation for student debt load is $4,200. The α is set to 0.05. The confidence interval for this hypothesis test would be __________.

In a survey, 21 people were asked how much they spent on their child's last birthday gift. The results were roughly bell-shaped with a mean of $30 and standard deviation of $14. Construct a confidence interval at a 80% confidence level.Give your answers to one decimal place. ______   ±  _______

True or false? If the original x distribution has a relatively small standard deviation, the confidence interval for ? will be relatively short. a. False. As ? decreases, E decreases, resulting in a longer confidence interval. b. True. As ? decreases, E increases, resulting in a shorter confidence interval.     c. True. As ? decreases, E decreases, resulting in a shorter confidence interval. e. False. As ? decreases, E increases, resulting in a longer confidence interval.

A pizza shop owner wishes to find the 99% confidence interval of the true mean cost of a large plain pizza. How large should the sample be if she wishes to be accurate to within $0.15? A previous study showed that the standard deviation of the price was $0.16. Round your final answer up to the next whole number.

1. On the Standford-Binet test, the mean IQ is 100. A class of 21 kindergarten pupils were tested with a resulting mean of 91 and a standard deviation of 6.59. What is the lower bound of the 90% confidence interval of the average IQ of the kindergarten pupils? 2. On the Standford-Binet test, the mean IQ is 100. A class of 21 kindergarten pupils were tested with a resulting mean of 94 and a standard deviation of 6.58. What is the margin of error of the 90% confidence interval of the average IQ of the kindergarten pupils? Note: Round your answer to 4 decimal places.

At a charter high school, the average GPA of a high school senior is known to be normally distributed. After a sample of 27 seniors is taken, the average GPA is found to be 2.85 and the sample variance is determined to be 0.16. Find a 95% confidence interval for the population mean GPA.   a. 2.5615 to 2.8585 b. 2.6358 to 3.0642 c. 2.6917 to 3.0083 d. 2.5167 to 2.9033

In a survey, 23 people were asked how much they spent on their child's last birthday gift. The results were roughly bell-shaped with a mean of $32 and standard deviation of $12. Construct a confidence interval at a 80% confidence level.Give your answers to one decimal place. ____± ____ Interpret your confidence interval in the context of this problem:

A soft drink manufacturer wishes to know how many soft drinks teenagers drink each week. They want to construct a 90% confidence interval with an error of no more than 0.08. A consultant has informed them that a previous study found the mean to be 5 soft drinks per week and found the standard deviation to be 1. What is the minimum sample size required to create the specified confidence interval? Round your answer up to the next integer.

Hunter is writing a report on the backgrounds of American presidents. He finds that the mean age of the 45 presidents is 55 years with the standard deviation of 6.59 years. Because Hunter took a statistics course, he calculates a 95% confidence interval for the mean age of all men who have been president to be 55 ± 1.98. Comment on this result.   Question 8 options:   Hunter can be 95% confident that the mean age of all presidents is 55 years.    95% of all the ages of the presidents lie between 55 ± 1.98.   Hunter should have taken a larger sample to reduce the margin of error.   Hunter is 95% confident that the mean age of all presidents lies between 53.02 and 56.98 years.    The confidence interval makes no sense since Hunter has the entire population of ages.