1.) You measure 37 turtles' weights, and find they have a mean weight of 30 ounces. Assume the population standard deviation is 9.2 ounces. Based on this, what is the maximal margin of error associated with a 95% confidence interval for the true population mean turtle weight. Give your answer as a decimal, to two places ______________________ ounces

2.) The lengths of adult males' hands are normally distributed with mean 190 mm and standard deviation is 7.4 mm. Suppose that 40 individuals are randomly chosen. Round all answers to 4 where possible.

1. What is the distribution of x? x ~ N( 190,_____)
2. For the group of 40, find the probability that the average hand length is less than 192. ____________
3. Find the first quartile for the average adult male hand length for this sample size. __________
4. For part b), is the assumption that the distribution is normal necessary? Yes or No

3.) You measure 50 randomly selected textbooks' weights, and find they have a mean weight of 40 ounces. Assume the population standard deviation is 2.4 ounces. Based on this, construct a 99% confidence interval for the true population mean textbook weight. Give your answers as decimals, to two places ____________________ < < _________________

4.) The amount of pollutants that are found in waterways near large cities is normally distributed with mean 9.7 ppm and standard deviation 1.8 ppm. 35 randomly selected large cities are studied. Round all answers to 4 decimal places where possible.

1. What is the distribution of X? X ~ N(______,___________) 9.7, 1.8 ?
2. What is the distribution of x? x ~ N(_______,_______) 9.7, _____?
3. What is the probability that one randomly selected city's waterway will have less than 10.5 ppm pollutants? ____________
4. For the 35 cities, find the probability that the average amount of pollutants is less than 10.5 ppm. _____________
5. For part d), is the assumption that the distribution is normal necessary? No or Yes
6. Find the IQR for the average of 35 cities. Q1 = ___________ ppm Q3 = ___________ ppm IQR: ____________ ppm

5.) A researcher wants to know how long it takes, on average, for a certain species of bacteria to divide. She watches 20 cells through a microscope and times how long it takes them to divide. She obtains the following data, in hours: 6.7, 7.2, 6.6, 10, 6.1, 6.1, 9.8, 5.7, 5, 5.3, 8.7, 6.9, 4.8, 7, 9.4, 8.3, 8.8, 8.9, 7.6, 6.6 Assuming the population standard deviation is =1.5=1.5, construct a 92% confidence interval for the average time it takes this species of bacteria to divide. x=_____________

2=_____________ z2=____________ Margin of Error: E= _____________ We are 92% confident that this species of bacteria takes, on average, between __________ hours and __________ hours to divide.

6.) Suppose that the amount of time that students spend studying in the library in one sitting is normally distributed with mean 42 minutes and standard deviation 20 minutes. A researcher observed 47 students who entered the library to study. Round all answers to 4 decimal places where possible.

1. What is the distribution of X? X ~ N(______,________)
2. What is the distribution of x? x ~ N(_______,_______)
3. What is the distribution of x? x ~ N(________,______)
4. If one randomly selected student is timed, find the probability that this student's time will be between 38 and 41 minutes. ____________
5. For the 47 students, find the probability that their average time studying is between 38 and 41 minutes. _______________
6. Find the probability that the randomly selected 47 students will have a total study time less than 2068 minutes. _____________
7. For part e) and f), is the assumption of normal necessary? Yes or No
8. The top 20% of the total study time for groups of 47 students will be given a sticker that says "Great dedication". What is the least total time that a group can study and still receive a sticker? _______________ minutes