In developing patient appointment schedules, a medical center wants to estimate the mean time that a staff member spends with each patient. How large a sample should be taken if the desired margin of error is two minutes at a 95% level of confidence? How large a sample should be taken for a 99% level of confidence? Use a planning value for the population standard deviation of 9 minutes.
95% Confidence (to the nearest whole number):
99% Confidence (to the nearest whole number):
Margin of error is 2 minutes that is
Margin of error=Critical Value* SE of the statistic=2
Critical Value of t for 95% interval= 2 (for sample size>30)
2=2*SD/Sqrt(Sample Size)
Sqrt(Sample Size)=SD=9
Sample Size=81
For 99% Confidence
Critical Value of t for 99% interval=2.62
Margin of Error =Critical Value*SE of the statistic =2
2=2.62*9/Sqrt(Sample Size)
2/(2.62*9)=1/(sqrt(sample Size))
1/0.048=sqrt(sample size)
11.792=sqrt(Sample Size)
Sample Size=139.06=140 approximately
Hence the answers are as follows
95% CI for 2 minutes of Margin of error we need Sample size of at least 81
99% CI for 2 minutes of Margin of error we need Sample size of at least 140
In developing patient appointment schedules, a medical center wants to estimate the mean time that a...
In developing patient appointment schedules, a medical center wants to estimate the mean time that a staff member spends with each patient. How large a sample should be taken if the desired margin of error is two minutes at a 95% level of confidence? How large a sample should be taken for a 99% level of confidence? Use a planning value for the population standard deviation of 6 minutes. 95% Confidence (to the nearest whole number): 99% Confidence (to the...
QUESTION 7 In developing patient appointment schedules, a medical center wants to estimate the mean time that a staff member spends with each patient. How large a sample should be taken if the desired margin of error is two minutes at a 99% level of confidence? Use a planning value for the population standard deviation of 8 minutes. 100 102 104 106
An advertising executive wants to estimate the mean weekly amount of time consumers spend watching traditional television daily. Based on previous studies, the standard deviation is assumed to be 22 minutes. The executive wants to estimate, with 99% confidence, the mean weekly amount of time to within ± 6 minutes. a. What sample size is needed? b. If 95% confidence is desired, how many consumers need to be selected? (Round up to the nearest integer.)
An advertising executive wants to estimate the mean weekly amount of time consumers spend watching traditional television daily. Based on previous studies, the standard deviation is assumed to be 26 minutes. The executive wants to estimate, with 99% confidence, the mean weekly amount of time to within ±33 minutes. a. What sample size is needed? b. If 95% confidence is desired, how many consumers need to be selected? a. The sample size required for 99% confidence is ___
Suppose it is desired to estimate the average time a customer spends in a particular store to within 5 minutes with 99% confidence. It is estimated that the range of the times a customer spends in the store is 90 minutes. How large a sample should be taken to get the desired interval? Right-click the link to use this Z table (The answer is NOT 135, or 134.37) (I believe the standard deviation is not 22.5) The answer is 60,...
A consumer group wants to estimate the mean electric bill for the month of April for single-family homes in a large city. Based on studies conducted for other cities, the standard deviation is assumed to be $24. The group wants to estimate, with 99% confidence, the mean bill for April to within $4 a. What sample size is needed? b. If 95% confidence is desired, how many homes need to be selected? Click the icon to view a table of...
Hays Medical Center wants to estimate the percentage of adults who exercise at least 1 hour per week. How large a sample should be selected in order to estimate this proportion with a 90% confidence level and a margin of error of at most 5%? (Assume no preliminary estimate of p-hat is available.)
An advertising media analyst wants to estimate the mean weekly amount of time consumers’ spend watching television daily. Based on previous studies, the standard deviation is assumed to be 20 minutes. The media analyst wasn’t to estimate, with 99% confidence, the mean weekly amount of time to within +/- 5 minutes. a) What sample sizes is needed b) If 95% confidence is desired, how many consumers need to be selected?
A teacher wants to estimate the mean time (in minutes) that students take to go from one classroom to the next. His research assistant uses the sample time of 40 students to report the confidence interval as [7.40, 8.60]. a. Find the sample mean time used to compute the confidence interval. (Round intermediate calculations to 4 decimal places and final answer to the nearest whole number.) Sample Mean - b. Determine the confidence level if the sample standard deviation used...
A high-tech company wants to estimate the mean number of years of college education its employees have completed. A good estimate of the standard deviation for the number of years of college is 1.32. How large a sample needs to be taken to estimate u to within 0.57 of a year with 95% confidence? (Round you answer up to the nearest whole number.) You may need to use the appropriate table in Appendix B to answer this question.