QMB 3200 Test 2

As a general guideline, the research hypothesis should be stated as the _____. a. alternative hypothesis b. tentative assumption c. hypothesis the researcher wants to disprove d. null hypothesis

a. alternative hypothesis

Which of the following is an improper form of the null and alternative hypotheses? a. H0: μ < μ0 and Ha: μ ≥ μ0 b. H0: μ ≥ μ0 and Ha: μ < μ0 c. H0: μ ≤ μ0 and Ha: μ > μ0 d. H0: μ = μ0 and Ha: μ ≠ μ0

a. H0: μ < μ0 and Ha: μ ≥ μ0

Your investment executive claims that the average yearly rate of return on the stocks she recommends is at least 10.0%. You plan on taking a sample to test her claim. The correct set of hypotheses is _____. a. H0: μ ≥ 10.0% Ha: μ < 10.0% b. H0: μ ≤ 10.0% Ha: μ > 10.0% c. H0: μ > 10.0% Ha: μ ≤ 10.0% d. H0: μ < 10.0% Ha: μ ≥ 10.0%

a. H0: μ ≥ 10.0% Ha: μ < 10.0%

The error of rejecting a true null hypothesis is _____. a. a Type I error b. committed when not enough information is available c. a Type II error d. committed when the sample size is too small

a. a Type I error

If a hypothesis is not rejected at a 5% level of significance, it will _____. a. also not be rejected at the 1% level b. always be rejected at the 1% level c. sometimes be rejected at the 1% level d. may be rejected or not rejected at the 1% level.

a. also not be rejected at the 1% level

When the rejection region is in the lower tail of the sampling distribution, the p-value is the area under the curve _____. a. less than or equal to the test statistic b. less than or equal to the critical value c. greater than or equal to the critical value d. greater than or equal to the test statistic

a. less than or equal to the test statistic

When each data value in one sample is matched with a corresponding data value in another sample, the samples are known as _____. a. matched samples b. corresponding samples c. dependent samples d. independent samples

a. matched samples

The level of significance is the _____. a. maximum allowable probability of a Type I error b. same as the p-value c. same as the confidence coefficient d. maximum allowable probability of a Type II error

a. maximum allowable probability of a Type I error

If a hypothesis is rejected at a 5% level of significance, it _____. a. may be rejected or not rejected at the 1% level b. will never be tested at the 1% level c. will always be accepted at the 1% level d. will always be rejected at the 1% level

a. may be rejected or not rejected at the 1% level

The least squares criterion is _____. a. min Σ(yi - ŷi)2 b. min Σ(yi - ȳ)2 c. min (Σyi - ŷi)2 d. min Σ(xi - yi)2

a. min Σ(yi - ŷi)2

Which of the following is correct? a. SSR = SSE + SST b. SST = SSR + SSE c. SSE = SSR + SST d. SST = (SSR)2

b. SST=SSR+SSE

If a hypothesis test leads to the rejection of the null hypothesis, a _____. a. Type II error must have been committed b. Type I error may have been committed c. Type I error must have been committed d. Type II error may have been committed

b. Type I error may have been committed

Two approaches to drawing a conclusion in a hypothesis test are _____. a. Type I and Type II b. p-value and critical value c. one-tailed and two-tailed d. null and alternative

b. p-value and critical value

When the p-value is used for hypothesis testing, the null hypothesis is rejected if _____. a. α < p-value b. p-value ≤ α c. p-value = z d. p-value > α

b. p-value ≤ α

If the alternative hypothesis is that proportion of items in population 1 is larger than the proportion of items in population 2, then the null hypothesis should be _____. a. p1 - p2 > 0 b. p1 - p2 ≤ 0 c. p1 - p2 < 0 d. p1 - p2 = 0

b. p1 - p2 ≤ 0

Independent simple random samples are selected to test the difference between the means of two populations whose variances are not known. The sample sizes are n1 = 32 and n2 = 40. The correct distribution to use is the _____ distribution. a. normal b. t c. uniform d. binomial

b. t

In the hypothesis testing procedure, α is _____. a. the critical value b. the level of significance c. 1 − level of significance d. the confidence level

b. the level of significance

The level of significance is symbolized by _____. a. σ b. α c. ρ d. β

b. α

A regression analysis between sales (in $1000s) and price (in dollars) resulted in the following equation: ŷ = 50,000 − 8x The above equation implies that an increase of _____. a. $8 in price is associated with an increase of $8,000 in sales b. $1 in price is associated with a decrease of $42,000 in sales c. $1 in price is associated with a decrease of $8,000 in sales d. $1 in price is associated with a decrease of $8 in sales

c. $1 in price is associated with a decrease of $8,000 in sales

For a one-tailed test (lower tail) with a sample size of 10 and a .10 level of significance the t value is _____. a. 1.383 b. -2.821 c. -1.383 d. -1.372

c. -1.383

A one-tailed test (lower tail) at a .063 level of significance has a z value of _____. a. -1.86 b. -1.96 c. -1.53 d. -1.645

c. -1.53

A two-tailed test at a 0.1010 level of significance has z values of _____. a. -0.83 and 0.83 b. -1.28 and 1.28 c. -1.64 and 1.64 d. -0.82 and 0.82

c. -1.64 and 1.64

For a two-tailed test with a sample size of 20 and a .20 level of significance, the t value is _____. a. 2.539 b. 2.528 c. 1.328 d. 1.325

c. 1.328

A Type I error is committed when _____. a. the critical value is greater than the value of the test statistic b. a true alternative hypothesis is not accepted c. a true null hypothesis is rejected d. sample data contradict the null hypothesis

c. a true null hypothesis is rejected

In a two-tailed hypothesis test, the null hypothesis should be rejected if the p-value is _____. a. less than or equal to 2α b. greater than or equal to 2α c. less than or equal to α d. greater than or equal to α

c. less than or equal to α

A company wants to identify which of two production methods has the smaller completion time. One sample of workers is randomly selected and each worker first uses one method and then uses the other method. The sampling procedure being used to collect completion time data is based on _____ samples. a. cross b. pooled c. matched d. independent

c. matched

The standard error of x̄1 - x̄2 is the _____. a. difference between the two means b. variance of x̄1 - x̄2 c. standard deviation of the sampling distribution of x̄1 - x̄2 d. variance of the sampling distribution of x̄1 - x̄2

c. standard deviation of the sampling distribution of x̄1 - x̄2

In hypothesis testing, the hypothesis tentatively assumed to be true is _____. a. the alternative hypothesis b. either the null or the alternative hypothesis, depending on the sample size. c. the null hypothesis d. always proven to be true

c. the null hypothesis

A one-tailed test (upper tail) at a .123 level of significance has a z value of _____. a. 1.54 b. 1.96 c. 1.645 d. 1.16

d. 1.16

Which of the following hypotheses is not a valid null hypothesis? a. H0: μ ≥ 0 b. H0: μ = 0 c. H0: μ ≤ 0 d. H0: μ < 0

d. H0: μ < 0

Independent simple random samples are selected to test the difference between the means of two populations whose standard deviations are not known. We are unwilling to assume that the population variances are equal. The sample sizes are n1 = 30 and n2 = 36. The correct distribution to use is the t distribution with how many degrees of freedom? a. 36 b. 30 c. 64 d. The correct degrees of freedom cannot be calculated without being given the sample standard deviations.

d. The correct degrees of freedom cannot be calculated without being given the sample standard deviations.

The proportion of the variation in the dependent variable y that is explained by the estimated regression equation is measured by the _____. a. correlation coefficient b. confidence interval estimate c. standard error of the estimate d. coefficient of determination

d. coefficient of determination

A one-tailed test is a hypothesis test in which rejection region is _____. a. in both tails of the sampling distribution b. only in the upper tail of the sampling distribution c. only in the lower tail of the sampling distribution d. in one tail of the sampling distribution

d. in one tail of the sampling distribution

When developing an interval estimate for the difference between two sample means, with sample sizes of n1 and n2, _____. a. n1 must be larger than n2 b. n1 must be equal to n2 c. n1 must be smaller than n2 d. n1 and n2 can be of different sizes

d. n1 and n2 can be of different sizes

In a simple regression analysis (where y is a dependent and x an independent variable), if the slope is positive, then it must be true that _____. a. the y-intercept is 0 b. there is a negative correlation between x and y c. there is no correlation between x and y d. there is a positive correlation between x and y

d. there is a positive correlation between x and y