A biologist needs to estimate the weight of all spiny lobsters on the Treasure Coast. To achieve this, the biologist collects a random sample of 20 spiny lobsters. The weights of each lobster in the sample are given below. Assume that the weights of all spiny lobsters on the Treasure Coast are normally distributed.

9.5	7.5	5.1	6.3	9.8	7.7	5.2	7.5	7.7	8.5
6.7	9.6	5	10	6.1	8.4	6.8	6	9.4	9.4

Determine the point estimate, x and the sample standard deviation, s. Round the solutions to four decimal places, if necessary. x= s= Using a 99.9% confidence level, determine the margin of error, E, and a confidence interval for the average weight of a spiny lobster on the Treasure Coast. Report the confidence interval using interval notation. Round solutions to two decimal places, if necessary. The margin of error is given by E=. A 99.9% confidence interval is given by .

A local non-profit group would like to estimate the proportion of residents of St. Lucie county who do not have health insurance. To help with this estimate, the non-profit surveyed a random sample of St. Lucie county residents and found that 24% did not have heath insurance. Determine the sample size required to limit the margin of error to within 0.078 of the population proportion for a 96% confidence interval. Round the solution up to the nearest whole number. n=

The Indian River County Health Department needs to estimate the proportion of all children in the county aged 19-35 months that are completely up to date with all state-recommended immunizations. The Indian River County Health Department found that 84% of a random sample of children in the county aged 19-35 months were completely up to date with all state-recommended immunizations. Find three different confidence intervals - one with sample size 586, one with sample size 739, and one with sample size 920. Assume that 84% of the children each sample are completely up to date with all state recommended immunizations. Notice how the sample size affects the margin of error and the width of the interval. Report confidence interval solutions using interval notation. Report all solutions in percent form, rounded to two decimal places, if necessary.

• When n=586, the margin of error for a 95% confidence interval is given by . When n=586, a 95% confidence interval is given by .
• When n=739, the margin of error for a 95% confidence interval is given by . When n=739, a 95% confidence interval is given by .
• When n=920, the margin of error for a 95% confidence interval is given by . When n=920, a 95% confidence interval is given by .

If the sample size is increased, leaving all other characteristics constant, the margin of error of the confidence interval will Select an answer increase decrease . If the sample size is increased, leaving all other characteristics constant, the width of the confidence interval will Select an answer decrease increase .

An economist at the Florida Department of Labor and Employment needs to estimate the unemployment rate in Okeechobee county. The economist found that 4.4% of a random sample of 387 county residents were unemployed. Find three different confidence intervals for the true proportion of Okeechobee county residents who are unemployed. Calculate one confidence interval with a 90% confidence level, one with a 95% confidence level, and one with a 96% confidence level. Notice how the confidence level affects the margin of error and the width of the interval. Report confidence interval solutions using interval notation. Express solutions in percent form, rounded to two decimal places, if necessary.

• The margin of error for a 90% confidence interval is given by E=Incorrect. A 90% confidence interval is given by Incorrect.
• The margin of error for a 95% confidence interval is given by E=Incorrect. A 95% confidence interval is given by Incorrect.
• The margin of error for a 96% confidence interval is given by E=Incorrect. A 96% confidence interval is given by Incorrect.

If the level of confidence is increased, leaving all other characteristics constant, the margin of error of the confidence interval will Select an answer decrease increase Correct . If the level of confidence is increased, leaving all other characteristics constant, the width of the confidence interval will

The bookstore at IRSC would like to estimate the proportion of students who prefer electronic textbooks (eBooks) over printed textbooks (hard copies). A random sample of 30 students was surveyed. Their preferences are listed below.

hard copy	hard copy	hard copy	hard copy	hard copy
eBook	eBook	eBook	eBook	hard copy
eBook	eBook	hard copy	eBook	hard copy
eBook	eBook	eBook	eBook	eBook
hard copy	eBook	eBook	hard copy	hard copy
eBook	hard copy	hard copy	eBook	hard copy

Determine the point estimate, p^ and the sample standard deviation, sp^. Round the sample proportion to four decimal places and round the standard deviation to six decimal places, if necessary. p^= sp^= Using a 90% confidence level, determine the margin of error, EE, and a confidence interval for the proportion of all students at the college who work prefer eBooks over printed textbooks. Report the confidence interval using interval notation. Report the solutions in percent form, rounded to two decimal places, if necessary. The margin of error is given by E=. A 90% confidence interval is given by . The margin of error for this confidence interval is quite large. What is the best way for the bookstore to achieve a confidence interval with a smaller margin of error?

• Increase the level of confidence
• Decrease the level of confidence
• Decrease the sample size
• Increase the sample size