The average public high school has 468 students with a standard deviation of 87. Answer the following problems. a. An investigator wants to estimate the proportion of freshmen at his University who currently smoke cigarettes (i.e., the prevalence of smoking). How many freshmen should be involved in the study to ensure that a 95% confidence interval estimate of the proportion of freshmen who smoke is within 5% of the true proportion? 400 396 350 385 b. Dylan wants to determine a 99 percent confidence interval for the true proportion of high school students in the area who attend their home basketball games.How large of a sample must he have to get a margin of error less than 0.04 ? Use the value p = 1/2 for the sample proportion. 1041 1020 1039 none of these c. An internet service provider wishes to estimate, to within one percentage error, the current proportion of all email that is spam, with 85% confidence. Last year the proportion that was spam was 71%. Estimate the minimum size sample required if the total email that is spam is 10,000. 2830 2993 2020 2900 d. The mean age of 20 youth volunteers in a community project is 17.5 years with a standard deviation of 2 years. If the sample comes from approximately normal distribution, what is the interval estimates of the population mean? Use 99% confidence level. 16.22 - 18.78 16.34 - 18.65 16.23 - 18.77 none of these
The average public high school has 468 students with a standard deviation of 87.
Answer the following problems.
a. An investigator wants to estimate the proportion of freshmen at his University who currently smoke cigarettes (i.e., the prevalence of smoking). How many freshmen should be involved in the study to ensure that a 95% confidence
400
396
350
385
b. Dylan wants to determine a 99 percent confidence interval for the true proportion of high school students in the area who attend their home basketball games.How large of a sample must he have to get a margin of error less than 0.04 ? Use the value p = 1/2 for the sample proportion.
1041
1020
1039
none of these
c. An internet service provider wishes to estimate, to within one percentage error, the current proportion of all email that is spam, with 85% confidence. Last year the proportion that was spam was 71%. Estimate the minimum size sample required if the total email that is spam is 10,000.
2830
2993
2020
2900
d. The mean age of 20 youth volunteers in a community project is 17.5 years with a standard deviation of 2 years. If the sample comes from approximately
16.22 - 18.78
16.34 - 18.65
16.23 - 18.77
none of these
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