ECON 221 Chapter 9

When conducting a hypothesis test concerning the population proportion, the value of the test statistic is calculated as _____________.

(p bar - P0) / (sqr. root P0(1-P0)squared / n))

A 99% confidence interval for the population mean yields the following results: [-3.79, 5.86]. At the 1% significance level, what decision should be made regarding the following hypothesis test with H0: u = 0, HA: u doesn't equal 0?

Do not reject H0; we cannot conclude that the mean differs from zero.

True or False: A Type II error is made when we reject the null hypothesis and the null hypothesis is actually false.

False

Expedia would like to test if the average round-trip airfare between Philadelphia and Dublin is less than $1,200. The correct hypothesis statement would be __________.

H0: u >= $1,200, HA: u < $1,200

True or False: A Type I error is committed when we reject the null hypothesis, which is actually true.

True

True or False: As a general guideline, we use the alternative hypothesis as a vehicle to establish something new, or contest the status quo, for which a corrective action may be required.

True

True or False: The null hypothesis typically corresponds to a presumed default state of nature (status quo).

True

When conducting a hypothesis test for a given sample size, if the probability of a Type I error decreases, then the ______________.

probability of incorrectly not rejecting the null hypothesis increases

If the p-value for a hypothesis test is 0.027 and the chosen level of significance is a = 0.05, then the correct conclusion is to _____________.

reject the null hypothesis

A schoolteacher is worried that the concentration of dangerous, cancer-causing radon gas in her classroom is greater than the safe level of 4pCi/L. The school samples the air for 36 days and finds an average concentration of 4.4pCi/L with a standard deviation of 1pCi/L. The value of the test statistic is ___________.

t35 = 2.40