1. We wish to calculate a confidence interval for an unknown population proportion given a sample of 35 successes out of 50 trials (sample proportion p = 0.7). The standard error implied by this sample is 0.0648. A 68% confidence interval calculated for the population proportion given these data is [0.6352, 0.7648]. The 95% confidenceinterval is [0.5730, 0.8270]. The 68% confidence interval is ________ (more accurate/less accurate) and _________ (more precise/less precise) than the 95% confidence interval.

2. Among the 325 First Class passengers aboard the Titanic, 203 survived, implying a sample proportion of 0.6246. A 95% confidence interval for the probability of survival among First Class passengers is [0.5720, 0.6773]. This means that there is a 95% probability that the probability of survival lies between 0.5720 and 0.6773. (true or false?)

3. Among the 325 First Class passengers aboard the Titanic, 203 survived, implying a sample proportion of 0.6246. A 95% credible interval for the probability of survival among First Class passengers is [0.5711, 0.6760]. This means that there is a 95% probability that the probability of survival lies between 0.5711 and 0.6760. (true or false?)

4. When we use sample statistics as point estimates of population parameters, we are almost always wrong. The difference between the sample statistic and the population parameter is known as: (select one)

-the margin of error

-the standard error

-a significant difference

-error

5. If we wish to increase the accuracy of a confidence interval, we need to ________ (increase/decrease) the confidence level. If we wish to make it harder to reject the null hypothesis (and therefore reduce the probability of committing a Type 1 error), we need to ________ (increase/decrease) the level of significance

6. An analysis of data on fertility and infant mortality rates for several French-speaking provinces in 19th century Switzerland suggests that the infant mortality rate increases as the fertility rate increases. A test for independence between these variables indicates a P-value of 0.00359. At the 0.05 significance level, these data ________(are not significant/are significant. This means that these two variables are ________(are not associated/are associated).

7. We often use the chi-square distribution to approximate the sampling distribution of the chi-square test statistic. The "degrees of freedom" or df parameter for this model influences its location, scale, and shape in the following ways:

-As df increases, the location _________ (decreases/increases).

-As df decreases, the scale _________ (decreases/increases).

-As df increases, the distribution becomes _________ (less/more) right-skewed.

-As the number of levels in the row variables increases, df _________ (increases/decreases).

-As the number of levels in the column variables increases, df ________(increases/decreases).