How large a sample should be selected to provide a 95% confidence interval with a margin of error of 8? Assume that the population standard deviation is 50. Round your answer to next whole number.

How large a sample should be selected to provide a 95% confidence interval with a margin of error of 3? Assume that the population standard deviation is 20. Round your answer to the next whole number

How large a sample should be selected to provide a 95% confidence interval with a margin of error of 7? Assume that the population standard deviation is 50. Round your answer to next whole number.

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Use the t-table or any statistical tool and report the t-score that you multiple by the standard error to form the margin of error for a 95% confidence interval for a mean with 5 observations.   a. 2.132   b. 2.776   c. 2.015   d. 2.571

How large a sample should be selected to provide a 95% confidence interval with a margin of error of 9? Assume that the population standard deviation is 10. Round your answer to next whole number.

To celebrate the end of final exams you and friends head to a favorite downtown restaurant. You find a street parking spot with a maximum of two hours. If you stay longer than two hours, you risk having your car towed away. No one has a watch or cellphone but you remember that the average time you spent at the same restaurant over your previous 16 visits is 1.5 hours, and you estimate the sample standard deviation to be about 20 minutes. You also need to factor in that it takes 8 minutes to walk to the restaurant and 8 minutes to walk back to your car (you are very certain about these two durations). (a) One of your friends is really worried that you won’t get back to the car in time and so the car might be towed away! Does your friend have good reason to be worried? Test at a 5% significance level whether the mean total time will be less than two hours. (b) You decide to leave the car parked at the street spot but it gets towed. What type of error have you committed?

A distribution of values is normal with a mean of 246.2 and a standard deviation of 99.5. Find P78, which is the score separating the bottom 78% from the top 22%. P78 Enter your answer as a number accurate to 4 decimal places.