Exam 9: Estimating the Value of a Parameter

Construct a 99% confidence interval for the population mean, μ. Assume the population has a normaldistribution. A group of 19 randomly selected employees has a mean age of 22.4 years with a standarddeviation of 3.8 years. Round to the nearest tenth.

A private opinion poll is conducted for a politician to determine what proportion of the population favorsadding more national parks. How large a sample is needed in order to be 90% confident that the sampleproportion will not differ from the true proportion by more than 5%?

Fifteen randomly selected men were asked to run on a treadmill for 6 minutes. After the 6 minutes, their pulseswere measured and the following data were obtained: 105 94 98 88 104 101 99 85 84 124 122 114 97 101 90

In a random sample of 60 dog owners enrolled in obedience training, it was determined that the mean amountof money spent per owner was $109.33 per class. Assuming the population standard deviation of the amountspent per owner is $12, construct and interpret a 95% confidence interval for the mean amount spent per ownerfor an obedience class.

Find the t-value such that the area left of the t-value is 0.025 with 17 degrees of freedom.

Find the critical t-value that corresponds to 90% confidence and n = 15.

If we wish to obtain a 98% confidence interval of a parameter using the bootstrap method, which percentiles ofthe resampled distribution will form the lower and upper bounds of the interval?

Determine the point estimate of the population mean and margin of error for the confidence interval withlower bound 7 and upper bound: 25.

A survey of 2690 musicians showed that 368 of them are left-handed. Find a point estimate for p, thepopulation proportion of musicians that are left-handed.

True or False? If no estimate of p exists when determining the sample size, we can use 0.5 in the formula to geta value for n.

Construct a 90% confidence interval for the population mean, μ. Assume the population has a normaldistribution. A sample of 15 randomly selected math majors has a grade point average of 2.86 with a standarddeviation of 0.78. Round to the nearest hundredth.

A university dean is interested in determining the proportion of students who receive some sort of financial aid. Rather than examine the records for all students, the dean randomly selects 200 students and finds that 118 of them are receiving financial aid. Use a 95 % confidence interval to estimate the true proportion of students on financial aid. Express the answer in the form $\hat { p } \pm E$ and round to the nearest thousandth.

95%

A college nurse obtained a random sample of 20 students from the college. Each student was asked if they weretaking antidepressants. In the data, a 1 indicates the student is taking antidepressants and a 0 indicates they arenot taking antidepressants. 0 0 1 0 1 1 0 0 0 0 0 1 0 0 0 0 0 1 0 1 Treat these data as a simple random sample of all students at the college. Explain the algorithm in using thebootstrap method with 1000 resamples to obtain a 99% confidence interval for the proportion of all students atthe college who are taking antidepressants.

A survey of 250 households showed 91 owned at least one snow blower. Find a point estimate for p, thepopulation proportion of households that own at least one snow blower.

What is the best point estimate for p in order to construct a confidence interval for p ?

When 385 junior college students were surveyed,170 said that they have previously owned a motorcycle. Finda point estimate for p, the population proportion of students who have previously owned a motorcycle.

The best point estimate for the standard deviation of a population is