Question 1

You want to obtain a sample to estimate how much parents spend on their kids birthday parties. Based on previous study, you believe the population standard deviation is approximately=78.8=78.8dollars. You would like to be 95% confident that your estimate is within 4 dollar(s) of average spending on the birthday parties. How many parents do you have to sample?

n= __________

Question 2

You want to obtain a sample to estimate a population mean. Based on previous evidence, you believe the population standard deviation is approximately=60.8=60.8. You would like to be 99% confident that your estimate is within 1 of the true population mean. How large of a sample size is required?Do not round mid-calculation. n= __________

Question 3

You want to obtain a sample to estimate how much parents spend on their kids birthday parties. Based on previous study, you believe the population standard deviation is approximately=51.6=51.6dollars. You would like to be 90% confident that your estimate is within 1.5 dollar(s) of average spending on the birthday parties. How many moms do you have to sample?Do not round mid-calculation. n= ___________ Try this with your statistics calculator, if you increases the confidence level, the sample size

• increases
• decreases

If you increases the error bound, the sample size

• increases
• decreases

Question 4

A labor rights group wants to determine the mean salary of app-based drivers. If she knows that the standard deviation is $1.8, how many drivers should she consider surveying to be 95% sure of knowing the mean will be within$0.74$0.74?

• 23
• 18
• 17
• 5
• 74

Question 5

SAT scores are normally distributed with a mean of 1,500 and a standard deviation of 300. An administrator at a college is interested in estimating the average SAT score of first-year students. If the administrator would like to limit the margin of error of the 92% confidence interval to 25 points, how many students should the administrator sample?Make sure to give a whole number answer.

Question 6

SAT scores are distributed with a mean of 1,500 and a standard deviation of 303. You are interested in estimating the average SAT score of first year students at your college. If you would like to limit the margin of error of your confidence interval to 30 points with 95 percent confidence, how many students should you sample? (Round up to a whole number of students.)

Question 7

A political candidate has asked you to conduct a poll to determine what percentage of people support him. If the candidate only wants a 8% margin of error at a 90% confidence level, what size of sample is needed? When finding the z-value, round it to four decimal places.

Question 8

Based on historical data in Oxnard college, we believe that 31% of freshmen do not visit their counselors regularly. For this year, you would like to obtain a new sample to estimate the proportiton of freshmen who do not visit their counselors regularly. You would like to be 99% confident that your estimate is within 1% of the true population proportion. How large of a sample size is required?Do not round mid-calculation. n= ___________

Question 9

You want to obtain a sample to estimate a population proportion. At this point in time, you have no reasonable preliminary estimation for the population proportion. You would like to be 95% confident that you estimate is within 2.5% of the true population proportion. How large of a sample size is required?Do not round mid-calculation. n=_______________

Question 10

You work for a marketing firm that has a large client in the automobile industry. You have been asked to estimate the proportion of households in Chicago that have two or more vehicles. You have been assigned to gather a random sample that could be used to estimate this proportion to within a 0.035 margin of error at a 95% level of confidence.

a) With no prior research, what sample size should you gather in order to obtain a 0.035 margin of error? Round your answerupto the nearest whole number.

n = ___________ households

b) Your firm has decided that your plan is too expensive, and they wish to reduce the sample size required. You conduct a small preliminary sample, and you obtain a sample proportion ofp=0.205p^=0.205. Using this new information.what sample size should you gather in order to obtain a 0.035 margin of error? Round your answerupto the nearest whole number.

n = ________households

Question 11

You want to obtain a sample to estimate a population proportion. Based on previous evidence, you believe the population proportion is approximately 66%. You would like to be 95% confident that your estimate is within 3% of the true population proportion. How large of a sample size is required?Do not round mid-calculation. n= ______

Question 12

A pollster wishes to estimate, with 99% confidence, the proportion of people who approve of how President Trump is performing his job.