Chapters 9-10 Review

•The distribution of Student's t is ________.

• •symmetrical

• •negatively skewed

• •positively skewed

• •a discrete probability distribution

•A sample standard deviation is the best point estimate of the ________.

• •population range

• •population skewness

• •population mode

• •population standard deviation

•A survey of 50 retail stores revealed that the average price of a microwave was $375, with a sample standard deviation of $20. If 90% and 95% confidence intervals were developed to estimate the true cost of the microwave, what similarities would they have?

• •Both have the same confidence level.

• •Both use the same critical t.

• •Both use the same critical z.

• •Both use the same point estimate of the population mean.

•When using Student's t to compute an interval estimate, ________.

• •we assume that the samples are collected from populations that are uniformly distributed

• •we estimate the population mean based on the sample mean

• •we use the z-distribution

• •we assume that the samples are collected from normally distributed populations

•If 95% and 98% confidence intervals were developed to estimate the true cost of an MP3 player with a known population standard deviation, what differences would they have?

• •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.

•A null hypothesis makes a claim about a ________.

• •population parameter

• •sample statistic

• •sample mean

• •type II error

•Define the level of significance.

• •It is the probability of a Type I error.

• •It is the probability of a Type II error.

• •It is a z-value of 1.96.

• •It is the beta error.

•If the alternate hypothesis states that µ ≠ 4,000, where is the rejection region for the hypothesis test?

• •In both tails

• •In the lower or left tail

• •In the upper or right tail

• •In the center

•If the critical z-value for a hypothesis test equals 2.45, what value of the test statistic would provide the least chance of making a Type I error?

• •3.74

• •1.07

• •2.46

• •4.56

What is a critical value?

• A value, determined from sample information, used to determine whether to reject the null hypothesis

• The dividing point between the region where the null hypothesis is rejection and the region where it is not rejected.

• A statement about a population parameter subject to verification.

• The probability of rejecting the null hypothesis when it is true.