1. The 95% confidence interval states that 95% of the sample means of a specified sample size selected from a population will lie within plus and minus 1.96 standard deviations of the hypothesized population mean. T or F
2. Which of the following is NOT necessary to determine how large a sample to select from a population?
Multiple Choice
The level of confidence in estimating the population parameter
The size of the population
The maximum allowable error in estimating the population parameter
An estimate of the population variation
3.
A university surveyed recent graduates of the English department about their starting salaries. Four hundred graduates returned the survey. The average salary was $25,000. Assume for purposes of this problem that the population standard deviation is known, and it is $2,500. What is the 95% confidence interval for the mean salary of all graduates from the English department?
Multiple Choice
$22,500 and $27,500
$24,755 and $25,245
$24,988 and $25,012
$24,600 and $25,600
4.
If 95% and 98% confidence intervals were calculated from the same sample data in order to estimate the true cost of an appliance with a known population standard deviation, what differences would there be between them?
Multiple Choice
The standard errors would be different.
The point estimates of the population mean would be different.
The sample sizes would be different.
The z-statistics would be different.
5.
A student wanted to construct a 95% confidence interval for the mean age of students in her statistics class. She randomly selected nine students. Their average age was 19.1 years with a sample standard deviation of 1.5 years. What is the best point estimate for the population mean?
Multiple Choice
2.1 years
1.5 years
19.1 years
9 years
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