- A financial analyst working for a financial consulting company wishes to find evidence that the average price-to-earnings ratio in the consumer industry is higher than the average price-to-earnings ratio in the banking industry. The alternative hypothesis is μconsumer > μbanking.
- A Type I error is rejecting a true null hypothesis. True
- A Type II error is failing to reject a false null hypothesis. True
- All of the following are assumptions of the error terms in the simple linear regression model except error terms are dependent on each other.
- An independent samples experiment is an experiment in which there is no relationship between the measurements in the different samples. True
- As standard deviation increases, sample size _____________ to achieve a specified level of confidence. Increases
- As the sample size ______________, the variation of the sampling distribution of x⎯⎯x¯ ___________. increases, decreases
- As the Type II error, β,of a statistical test increases, the power of the test _____________. Decreases
- Assuming that the null hypothesis is true, the ______________ is the probability of observing a value of the test statistic that is at least as extreme as the value actually computed from the sample data. p-value
- Assuming the same level of significance α, as the sample size increases, the value of tα/2 approaches the value of zα/2. False
- Consider two population distributions labeled A and B. Distribution A is highly skewed and nonnormal, while distribution B is slightly skewed and near normal. In order for the sampling distributions of A and B to achieve the same degree of normality, population A will require a larger sample size.
- First, a 90 percent confidence interval is constructed from a sample size of 100. Then, for the same identical data, a 92 percent confidence interval is constructed. The width of the 90 percent interval is wider than the 92 percent confidence interval. False
- For a fixed sample size, the lower we set α, the higher is the ___________. Type 2 error
- For any sampled population, the population of all sample means is approximately normally distributed. False
- For the same set of observations on a specified dependent variable, two different independent variables were used to develop two separate simple linear regression models. A portion of the results is presented below.
Based on the results given above, we can conclude that a prediction based on Model 1 is better than a prediction based on Model 2. - Given the following information about a hypothesis test of the difference between two means based on independent random samples, which one of the following is the correct rejection region at a significance level of .05? Reject H0 if t > 1.721
- If r = −1, then we can conclude that there is a perfect relationship between X and Y. True
- If the sampled population has a mean of 48 and standard deviation of 16, then the mean and the standard deviation for the sampling distribution of x⎯⎯x¯ for n = 16 are 48 and 4
- If we are testing the difference between the means of two normally distributed independent populations with samples of n1 = 10, n2 = 10, the degrees of freedom for the t statistic is ___ 18
- If we are testing the hypothesis about the mean of a population of paired differences with samples of n1 = 10, n2 = 10, the degrees of freedom for the t statistic is ___ 9
- In a simple linear regression analysis, the correlation coefficient (a) and the slope (b) ___________ have the same sign. Always
- In an experiment involving matched pairs, a sample of 12 pairs of observations is collected. The degrees of freedom for the t statistic is 10. True
- In order to test the effectiveness of a drug called XZR designed to reduce cholesterol levels, the cholesterol levels of 9 heart patients are measured before they are given the drug. The same 9 patients use XZR for two continuous months. After two months of continuous use, the cholesterol levels are measured again. The comparison of cholesterol levels before versus after administering the drug is an example of testing the difference between matched pairs from two dependent populations.
- In simple regression analysis, r2 is a percentage measure and measures the proportion of the variation explained by the simple linear regression model. True
- In testing for the equality of means from two independent populations, if the hypothesis of equal population means is rejected at α = .01, it will __________ be rejected at α = .05 always
- in testing the difference between two means from two normally distributed independent populations, the distribution of the difference in sample means will be normally distributed.
- The Central Limit Theorem states that as sample size increases, the population distribution more closely approximates a normal distribution. False
- The Central Limit Theorem states that as the sample size increases, the distribution of the sample ____________ approaches the normal distribution Means
- The exact spread of the t distribution depends on the _______ number of degrees of freedom
- The larger the p-value, the more we doubt the null hypothesis. False
- The least squares regression line minimizes the sum of the squared differences between actual and predicted Y values.
- The population of all sample proportions has a normal distribution if the sample size (n) is sufficiently large. The rule of thumb for ensuring that n is sufficiently large is np ≥ 5 and n(1 − p) ≥ 5.
- The residual is the difference between the observed value of the dependent variable and the predicted value of the dependent variable. True
- The sampling distribution of x⎯⎯x¯ must be a normal distribution with mean = 0 and standard deviation = 1. False
- The slope of the simple linear regression equation represents the average change in the value of the dependent variable per unit change in the independent variable (X). True
- The standard deviation of all possible sample proportions increases as the sample size increases. False
- The standard error of the sample mean is s/√n. False
- The t distribution always has n degrees of freedom. False
- The t distribution approaches the _______________ distribution as the sample size ___________. z;
increases - The width of a confidence interval will be narrower for 90 percent confidence than for 95 percent confidence.
- Using the p-value rule for a population proportion or mean, if the level of significance is less than the p-value, the null hypothesis is rejected False
- When comparing two independent population means, if n1 = 13 and n2 = 10, degrees of freedom for the t statistic is 22 False
- When constructing a confidence interval for a population mean, if a population is normally distributed and a small sample is taken, then the distribution of X⎯⎯⎯X¯ is based on the ____________ distribution T
- When determining the sample size, if the value found is not an integer initially, you should ____________ choose the next highest integer value. always
- When testing a hypothesis about a single mean, if the sample size is 51 and the population standard deviation is known, the correct test statistic to use is ___________. Z
- When testing the difference between two population proportions using large independent random samples, the __________ test statistic is used Z
- When the margin of error is added to and subtracted from the sample mean, an interval is formed that will contain μ with a probability of (1 − α). True
- When the population is normally distributed and the population standard deviation σ is unknown, then for any sample size n, the sampling distribution of x⎯⎯x¯ is based on the z distribution. False
- Whenever the population has a normal distribution, the sampling distribution of x⎯⎯x¯ is a normal or near normal distribution for any sample size.
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